Enhancing Overall Site Drainage with Gravel Trenches

Enhancing Overall Site Drainage with Gravel Trenches

Explanation of how gravel trenches contribute to improved drainage systems.


Certainly! French drains redirect water away from homes to prevent foundation damage foundation repair service areas entrance stairs. Let's delve into the topic of enhancing overall site drainage with gravel trenches, focusing on how these structures contribute to improved drainage systems.

Gravel trenches play a pivotal role in optimizing site drainage, serving as a natural and effective solution to manage water flow. At their core, gravel trenches are essentially excavated channels filled with gravel or similarly permeable materials. The primary function of these trenches is to facilitate the rapid movement of water away from areas where it might cause damage or inconvenience.

The effectiveness of gravel trenches in enhancing drainage can be attributed to several key factors. Firstly, the permeability of gravel allows water to infiltrate and percolate through the material quickly. This rapid infiltration reduces the likelihood of surface water pooling, which can lead to issues such as soil erosion, foundation damage, or even flooding in extreme cases. By providing a direct pathway for water to move through the ground, gravel trenches ensure that excess water is efficiently dispersed away from critical areas.

Moreover, gravel trenches contribute to improved drainage by enhancing the overall permeability of the site. When rainwater encounters a gravel-filled trench, it is immediately absorbed and directed downward, bypassing less permeable soil layers. This not only speeds up the drainage process but also helps to mitigate the impact of heavy rainfall events by reducing surface runoff. As a result, the risk of water-related problems is significantly diminished, leading to a more stable and resilient site.

Another important aspect of gravel trenches is their ability to complement other drainage solutions. They can be integrated into existing drainage systems, such as French drains or swales, to create a comprehensive network for managing water flow. This synergy allows for more efficient drainage across the site, ensuring that water is directed to appropriate outlets or retention areas where it can be safely stored or released.

In conclusion, gravel trenches are a valuable component in the enhancement of overall site drainage. Their ability to rapidly infiltrate and disperse water, improve site permeability, and integrate with other drainage solutions makes them an effective and sustainable choice for managing water flow. By incorporating gravel trenches into drainage strategies, property owners and landscape managers can significantly reduce the risk of water-related issues, ensuring a drier, safer, and more enjoyable environment for all.

Step-by-step guide on assessing the current drainage issues around a residential foundation.


Certainly!

When it comes to enhancing the overall site drainage around a residential foundation, one effective method is the installation of gravel trenches. However, before diving into any improvement project, it's crucial to assess the current drainage issues. Here's a step-by-step guide to help you evaluate the existing drainage problems around your home's foundation:

1. **Observation During Rainfall**: The first step is to observe your property during and after a rainfall. Take note of any areas where water seems to pool or flow towards the foundation. This will give you a preliminary idea of where the drainage issues might be.

2. **Check the Grading**: Proper grading is essential for effective drainage. Walk around your property and check if the ground slopes away from the foundation. If the slope is towards the house, water will naturally be directed towards the foundation, leading to potential issues.

3. **Inspect the Gutters and Downspouts**: Clogged or misdirected gutters can contribute to foundation drainage problems. Ensure that your gutters are clean and that the downspouts direct water away from the foundation.

4. **Look for Signs of Water Intrusion**: Check the basement or crawl space for any signs of moisture, mold, or musty odors. These can be indicators of water intrusion due to poor drainage.

5. **Evaluate the Soil Type**: Different soil types drain at different rates. Clay soils, for instance, retain water and can lead to drainage issues. Knowing your soil type can help in determining the best drainage solution.

6. **Assess Plant and Tree Roots**: Large trees or dense plant roots can disrupt the natural flow of water and even damage drainage systems. Take note of any such vegetation close to the foundation.

7. **Professional Evaluation**: If you're unsure about any of the above steps or if the drainage issues seem severe, it might be beneficial to consult with a professional drainage expert. They can provide a more detailed assessment and recommend the best solutions.

By following this guide, you'll be well-equipped to identify the current drainage issues around your residential foundation. Once assessed, you can then consider solutions like gravel trenches to enhance the overall site drainage and protect your home's foundation.

Detailed instructions for designing an effective gravel trench layout tailored to specific residential properties.


Designing an effective gravel trench layout for enhancing overall site drainage in residential properties involves several critical steps, tailored to the unique topography and drainage needs of each site. Here's a detailed guide to help navigate the process:

1. **Assess the Site**: Start by conducting a thorough site analysis. Identify the natural slope, existing drainage patterns, and areas prone to water accumulation. This assessment will help determine the optimal location for the gravel trenches.

2. **Determine Trench Dimensions**: The size and depth of the trenches depend on the volume of water they need to manage. Typically, trenches should be at least 12 inches wide and 18-24 inches deep to ensure adequate capacity. Deeper trenches may be necessary in areas with heavy rainfall or poor soil drainage.

3. **Select Appropriate Gravel**: Choose clean, angular gravel with a size of 3/4 inch to 1 inch. This type of gravel ensures good permeability and stability. Avoid rounded gravel, as it can compact over time and reduce the trench's effectiveness.

4. **Plan the Trench Layout**: Design the trench layout to direct water away from the house and other structures. Use a slope of at least 1% to ensure gravity aids in drainage. Consider incorporating multiple trenches in a herringbone pattern for larger properties to maximize water dispersal.

5. **Incorporate Perforated Pipes**: Install perforated pipes within the trenches to facilitate faster water movement. Ensure the pipes are laid on a bed of smaller gravel to prevent clogging and allow water to enter the pipes freely.

6. **Use Geotextile Fabric**: Line the trenches with geotextile fabric to prevent soil from mixing with the gravel. This fabric allows water to pass through while keeping the gravel clean and maintaining its permeability.

7. **Backfill and Compact**: After placing the gravel and pipes, backfill the trenches with the original soil. Compact the soil gently to avoid displacing the gravel but ensure the surface is level and stable.

8. **Monitor and Maintain**: Regularly inspect the gravel trenches for any signs of clogging or displacement. Clear any debris that may accumulate on the surface to maintain optimal functionality.

By following these detailed instructions, homeowners can create an effective gravel trench system tailored to their specific property, significantly enhancing site drainage and protecting their investment from water-related damage.

Overview of the materials and tools required for constructing gravel trenches.


Certainly! When it comes to enhancing overall site drainage with gravel trenches, understanding the materials and tools required is crucial for a successful project. Let's delve into what you'll need.

Firstly, the primary material for gravel trenches is, unsurprisingly, gravel. Opt for clean, angular gravel with a size that ensures good drainage yet prevents soil from washing into the trench. A common choice is 3/4 inch gravel. It's also beneficial to line the trench with a geotextile fabric. This fabric allows water to pass through while preventing soil migration into the gravel, ensuring the trench remains effective over time.

In terms of tools, you'll need a shovel for digging the trench. A spade with a sharp edge works best for clean cuts. Depending on the size of the area, a trenching machine might be a wise investment to save time and labor. A tamper will be useful to compact the gravel once it's in place, ensuring a stable and effective drainage system. Don't forget safety gear such as gloves and eye protection, especially if you're using machinery.

Lastly, consider the layout and design of your gravel trench. This will influence the quantity of materials you'll need. A well-planned design, taking into account the natural slope of the land and the areas most affected by water accumulation, will maximize the efficiency of your drainage system.

In summary, constructing gravel trenches for enhanced site drainage involves selecting the right type of gravel, using geotextile fabric for lining, and employing appropriate tools like shovels, possibly a trenching machine, and a tamper. Safety and careful planning are also key components of a successful project.

Comprehensive walkthrough of the gravel trench installation process, including excavation, gravel placement, and compaction techniques.


Sure, here's a comprehensive walkthrough of the gravel trench installation process aimed at enhancing overall site drainage:

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When it comes to improving site drainage, gravel trenches are a highly effective solution. They help redirect water away from problem areas, reducing the risk of flooding, erosion, and structural damage. Let's dive into a step-by-step guide on how to install gravel trenches, covering excavation, gravel placement, and compaction techniques.

**1. Planning and Design**
Before you start digging, it's crucial to plan your gravel trench system. Identify the areas with poor drainage and determine the best route for the trenches. Consider the natural slope of the land and where water tends to accumulate. Design your trenches to direct water towards a suitable discharge point, such as a storm drain or a dry well.

**2. Excavation**
Once your design is ready, it's time to excavate the trenches. Use a shovel or a trenching machine to dig trenches that are typically 12 to 18 inches wide and 18 to 24 inches deep. The depth and width may vary depending on the specific drainage needs of your site. Ensure that the trenches have a consistent slope, usually about 1% grade, to facilitate proper water flow.

**3. Preparing the Trench**
After excavation, it's important to prepare the trench for gravel placement. Remove any roots, rocks, or debris that could impede water flow. You may also want to line the bottom of the trench with a geotextile fabric. This fabric allows water to permeate while preventing soil from mixing with the gravel, which can reduce the effectiveness of the trench over time.

**4. Gravel Placement**
Now, it's time to fill the trench with gravel. Use clean, angular gravel with a size of 3/4 inch to 1-1/2 inches. Start by placing a layer of gravel at the bottom of the trench, about 6 inches thick. This initial layer should be compacted using a plate compactor or a jumping jack to ensure stability.

**5. Continuing Gravel Layers**
Add subsequent layers of gravel, compacting each layer thoroughly before adding the next. This process ensures that the trench remains permeable and can handle the volume of water it's designed to manage. Continue until the trench is filled to the desired level, usually just below the surface to avoid disrupting the landscape.

**6. Final Compaction**
Once the trench is filled with gravel, give the entire area a final compaction. This step is crucial as it ensures that the gravel settles properly and creates a stable, permeable structure. Walk over the compacted gravel to check for any soft spots and add more gravel if necessary.

**7. Backfilling and Landscape Restoration**
After compaction, you can backfill the trench with topsoil, leaving a slight depression to allow for water collection. Replace any plants or sod that were removed during excavation. Water the area gently to help the soil settle.

**8. Maintenance**
Regular maintenance is key to ensuring the longevity and effectiveness of your gravel trenches. Check for any blockages or compaction issues and clear away any debris that may accumulate.

By following these steps, you can effectively install gravel trenches to enhance your site's drainage, protecting your property from water-related issues and promoting a healthier landscape.

Maintenance tips for ensuring the longevity and effectiveness of gravel trenches in residential drainage systems.


Certainly! Here's a human-like essay on maintenance tips for ensuring the longevity and effectiveness of gravel trenches in residential drainage systems:

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Maintaining gravel trenches in residential drainage systems is crucial for ensuring they remain effective and long-lasting. These trenches play a vital role in managing water flow and preventing issues like flooding and soil erosion. Here are some practical maintenance tips to keep your gravel trenches in top condition.

Firstly, regular inspections are key. Take the time to check your gravel trenches at least once a season. Look for any signs of clogging, such as standing water or reduced water flow. Early detection of issues can prevent more significant problems down the line.

Secondly, keep the area around the trenches clear of debris. Leaves, twigs, and other organic matter can accumulate and block the gravel, hindering its drainage capabilities. Use a rake or a leaf blower to clean the area periodically.

Thirdly, consider the vegetation near your gravel trenches. While plants can be beneficial for stabilizing the soil, overgrown roots can invade the trenches and cause blockages. Trim back any invasive roots and avoid planting large shrubs or trees too close to the trenches.

Fourthly, ensure that the gravel itself remains clean and free-flowing. Over time, smaller particles can wash into the trench and reduce its effectiveness. If you notice a significant buildup of fine sediments, it may be necessary to flush the trench or replace the gravel.

Lastly, pay attention to the overall landscape. Ensure that the ground slopes away from your home and towards the gravel trenches. This design helps channel water into the trenches more effectively. If you notice any changes in the landscape that could affect water flow, make adjustments as needed.

In conclusion, maintaining gravel trenches in residential drainage systems requires a bit of effort, but the results are well worth it. Regular inspections, clearing debris, managing vegetation, keeping the gravel clean, and monitoring the landscape are all essential practices. By following these tips, you can ensure that your gravel trenches continue to provide effective drainage, protecting your property and enhancing the overall site drainage.

Case studies or examples showcasing successful residential foundation repair projects that incorporated gravel trenches for enhanced drainage.


Sure, here's a short essay on the topic:

Enhancing Overall Site Drainage with Gravel Trenches: Case Studies and Examples

Incorporating gravel trenches in residential foundation repair projects has proven to be a successful strategy for enhancing overall site drainage. This method not only addresses existing issues but also provides a long-term solution to prevent future problems. Let's explore a few case studies that showcase the effectiveness of this approach.

Case Study 1: The Suburban Home Renovation
In a suburban neighborhood, a homeowner noticed cracks in their foundation and damp basement walls. After a thorough inspection, it was determined that poor drainage was the primary cause. The solution involved excavating trenches around the foundation and filling them with gravel. This created a network of channels that directed water away from the house. Post-repair, the homeowner reported a significant reduction in moisture levels and no further foundation issues, highlighting the success of the gravel trench method.

Case Study 2: The Hillside House
A house built on a hillside faced severe foundation problems due to water accumulation. The repair team decided to implement a comprehensive drainage system that included gravel trenches. These trenches were strategically placed to capture and redirect water flow away from the foundation. Additionally, perforated pipes were installed within the trenches to enhance water movement. The result was a dry basement and a stable foundation, even during heavy rains.

Case Study 3: The Urban Townhouse
In an urban setting, a townhouse complex experienced foundation settling due to inadequate drainage. The repair project involved creating gravel trenches along the perimeter of the buildings. These trenches were connected to a main drainage line that led to a storm sewer. The intervention not only stabilized the foundations but also improved the overall aesthetics of the property by reducing waterlogging in the surrounding areas.

These case studies demonstrate the effectiveness of gravel trenches in enhancing site drainage and resolving foundation issues. By providing a clear path for water to move away from the foundation, this method ensures long-lasting stability and prevents future drainage-related problems. Homeowners and contractors alike can draw inspiration from these successful projects when faced with similar challenges.



Interior of part of a damaged home in New Orleans after Hurricane Katrina
Family photographs damaged by flooding
A smaller and more minor water spot caused by rainwater leaking through a roof

Water damage describes various possible losses caused by water intruding where it will enable attack of a material or system by destructive processes such as rotting of wood, mold growth, bacteria growth, rusting of steel, swelling of composite woods, de-laminating of materials such as plywood, short-circuiting of electrical devices, etc.

The damage may be imperceptibly slow and minor such as water spots that could eventually mar a surface, or it may be instantaneous and catastrophic such as burst pipes and flooding. However fast it occurs, water damage is a major contributor to loss of property.

An insurance policy may or may not cover the costs associated with water damage and the process of water damage restoration. While a common cause of residential water damage is often the failure of a sump pump, many homeowner's insurance policies do not cover the associated costs without an addendum which adds to the monthly premium of the policy. Often the verbiage of this addendum is similar to "Sewer and Drain Coverage".

In the United States, those individuals who are affected by wide-scale flooding may have the ability to apply for government and FEMA grants through the Individual Assistance program.[1] On a larger level, businesses, cities, and communities can apply to the FEMA Public Assistance program for funds to assist after a large flood. For example, the city of Fond du Lac Wisconsin received $1.2 million FEMA grant after flooding in June 2008. The program allows the city to purchase the water damaged properties, demolish the structures, and turn the former land into public green space.[citation needed]

Causes

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Water damage can originate by different sources such as a broken dishwasher hose, a washing machine overflow, a dishwasher leakage, broken/leaking pipes, flood waters, groundwater seepage, building envelope failures (leaking roof, windows, doors, siding, etc.) and clogged toilets. According to the Environmental Protection Agency, 13.7% of all water used in the home today can be attributed to plumbing leaks.[2] On average that is approximately 10,000 gallons of water per year wasted by leaks for each US home. A tiny, 1/8-inch crack in a pipe can release up to 250 gallons of water a day.[3] According to Claims Magazine in August 2000, broken water pipes ranked second to hurricanes in terms of both the number of homes damaged and the amount of claims (on average $50,000 per insurance claim[citation needed]) costs in the US.[4] Experts suggest that homeowners inspect and replace worn pipe fittings and hose connections to all household appliances that use water at least once a year. This includes washing machines, dishwashers, kitchen sinks, and bathroom lavatories, refrigerator icemakers, water softeners, and humidifiers. A few US companies offer whole-house leak protection systems utilizing flow-based technologies. A number of insurance companies offer policyholders reduced rates for installing a whole-house leak protection system.

As far as insurance coverage is concerned, damage caused by surface water intrusion to the dwelling is considered flood damage and is normally excluded from coverage under traditional homeowners' insurance. Surface water is water that enters the dwelling from the surface of the ground because of inundation or insufficient drainage and causes loss to the dwelling. Coverage for surface water intrusion[5] to the dwelling would usually require a separate flood insurance policy.

Categories

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There are three basic categories of water damage, based on the level of contamination.

Category 1 Water - Refers to a source of water that does not pose substantial threat to humans and classified as "clean water". Examples are broken water supply lines, tub or sink overflows or appliance malfunctions that involves water supply lines.

Category 2 Water - Refers to a source of water that contains a significant degree of chemical, biological or physical contaminants and causes discomfort or sickness when consumed or even exposed to. Known as "grey water". This type carries microorganisms and nutrients of micro-organisms. Examples are toilet bowls with urine (no feces), sump pump failures, seepage due to hydrostatic failure and water discharge from dishwashers or washing machines.

Category 3 Water - Known as "black water" and is grossly unsanitary. This water contains unsanitary agents, harmful bacteria and fungi, causing severe discomfort or sickness. Type 3 category are contaminated water sources that affect the indoor environment. This category includes water sources from sewage, seawater, rising water from rivers or streams, storm surge, ground surface water or standing water. Category 2 Water or Grey Water that is not promptly removed from the structure and or have remained stagnant may be re classified as Category 3 Water. Toilet back flows that originates from beyond the toilet trap is considered black water contamination regardless of visible content or color.[6]

Classes

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Class of water damage is determined by the probable rate of evaporation based on the type of materials affected, or wet, in the room or space that was flooded. Determining the class of water damage is an important first step, and will determine the amount and type of equipment utilized to dry-down the structure.[7]

Class 1 - Slow Rate of Evaporation. Affects only a portion of a room. Materials have a low permeance/porosity. Minimum moisture is absorbed by the materials. **IICRC s500 2016 update adds that class 1 be indicated when <5% of the total square footage of a room (ceiling+walls+floor) are affected **

Class 2 - Fast Rate of Evaporation. Water affects the entire room of carpet and cushion. May have wicked up the walls, but not more than 24 inches. **IICRC s500 2016 update adds that class 2 be indicated when 5% to 40% of the total square footage of a room (ceiling+walls+floor) are affected **

Class 3 - Fastest Rate of Evaporation. Water generally comes from overhead, affecting the entire area; walls, ceilings, insulation, carpet, cushion, etc. **IICRC s500 2016 update adds that class 3 be indicated when >40% of the total square footage of a room (ceiling+walls+floor) are affected **

Class 4 - Specialty Drying Situations. Involves materials with a very low permeance/porosity, such as hardwood floors, concrete, crawlspaces, gypcrete, plaster, etc. Drying generally requires very low specific humidity to accomplish drying.

Restoration

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Water damage restoration can be performed by property management teams, building maintenance personnel, or by the homeowners themselves; however, contacting a certified professional water damage restoration specialist is often regarded as the safest way to restore water damaged property. Certified professional water damage restoration specialists utilize psychrometrics to monitor the drying process.[8]

Standards and regulation

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While there are currently no government regulations in the United States dictating procedures, two certifying bodies, the Institute of Inspection Cleaning and Restoration Certification (IICRC) and the RIA, do recommend standards of care. The current IICRC standard is ANSI/IICRC S500-2021.[9] It is the collaborative work of the IICRC, SCRT, IEI, IAQA, and NADCA.

Fire and Water Restoration companies are regulated by the appropriate state's Department of Consumer Affairs - usually the state contractors license board. In California, all Fire and Water Restoration companies must register with the California Contractors State License Board.[10] Presently, the California Contractors State License Board has no specific classification for "water and fire damage restoration."

Procedures

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Water damage restoration is often prefaced by a loss assessment and evaluation of affected materials. The damaged area is inspected with water sensing equipment such as probes and other infrared tools in order to determine the source of the damage and possible extent of areas affected. Emergency mitigation services are the first order of business. Controlling the source of water, removal of non-salvageable materials, water extraction and pre-cleaning of impacted materials are all part of the mitigation process. Restoration services would then be rendered to the property in order to dry the structure, stabilize building materials, sanitize any affected or cross-contaminated areas, and deodorize all affected areas and materials. After the labor is completed, water damage equipment including air movers, air scrubbers, dehumidifiers, wood floor drying systems, and sub-floor drying equipment is left in the residence. The goal of the drying process is to stabilize the moisture content of impacted materials below 15%, the generally accepted threshold for microbial amplification. Industry standards state that drying vendors should return at regular time intervals, preferably every twenty-four hours, to monitor the equipment, temperature, humidity, and moisture content of the affected walls and contents.[6] In conclusion, key aspects of water damage restoration include fast action, adequate equipment, moisture measurements, and structural drying. Dehumidification is especially crucial for structural components affected by water damage, such as wooden beams, flooring, and drywall.

See also

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  • Indoor mold

References

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  1. ^ "Individual Disaster Assistance". DisasterAssistance.gov. Retrieved 2009-09-28.
  2. ^ "How We Use Water". 16 January 2017.
  3. ^ The University of Maine Corporate Extension – www.umext.maine.edu
  4. ^ Herndon Jr., Everette L.; Yang, Chin S. (August 2000). "Mold & Mildew: A Creeping Catastrophe". Claims Magazine. Archived from the original on 2000-08-15. Retrieved November 4, 2016.
  5. ^ Moisture Control Guidance for Building Design, Construction and Maintenance. December 2013.
  6. ^ "Water Damage Restoration Guideline" (PDF). Northern Arizona University. Archived from the original (PDF) on 2013-06-26. Retrieved 2 September 2014.
  7. ^ "The Basics Of Water Damage Restoration Training". www.iicrc.org. Retrieved 2016-11-03.
  8. ^ "Chapter 6: Psychrometry and the Science of Drying". IICRC Standards Subscription Site. Institute of Inspection, Cleaning and Restoration Certification. Retrieved 27 September 2020.
  9. ^ "ANSI/IICRC S500 Water Damage Restoration". IICRC. 22 December 2020. Retrieved 14 February 2022.
  10. ^ "California Contractors State License Board". State of California. Retrieved 2010-08-29.

 

Boston's Big Dig presented geotechnical challenges in an urban environment.
Precast concrete retaining wall
A typical cross-section of a slope used in two-dimensional analyzes.

Geotechnical engineering, also known as geotechnics, is the branch of civil engineering concerned with the engineering behavior of earth materials. It uses the principles of soil mechanics and rock mechanics to solve its engineering problems. It also relies on knowledge of geology, hydrology, geophysics, and other related sciences.

Geotechnical engineering has applications in military engineering, mining engineering, petroleum engineering, coastal engineering, and offshore construction. The fields of geotechnical engineering and engineering geology have overlapping knowledge areas. However, while geotechnical engineering is a specialty of civil engineering, engineering geology is a specialty of geology.

History

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Humans have historically used soil as a material for flood control, irrigation purposes, burial sites, building foundations, and construction materials for buildings. Dykes, dams, and canals dating back to at least 2000 BCE—found in parts of ancient Egypt, ancient Mesopotamia, the Fertile Crescent, and the early settlements of Mohenjo Daro and Harappa in the Indus valley—provide evidence for early activities linked to irrigation and flood control. As cities expanded, structures were erected and supported by formalized foundations. The ancient Greeks notably constructed pad footings and strip-and-raft foundations. Until the 18th century, however, no theoretical basis for soil design had been developed, and the discipline was more of an art than a science, relying on experience.[1]

Several foundation-related engineering problems, such as the Leaning Tower of Pisa, prompted scientists to begin taking a more scientific-based approach to examining the subsurface. The earliest advances occurred in the development of earth pressure theories for the construction of retaining walls. Henri Gautier, a French royal engineer, recognized the "natural slope" of different soils in 1717, an idea later known as the soil's angle of repose. Around the same time, a rudimentary soil classification system was also developed based on a material's unit weight, which is no longer considered a good indication of soil type.[1][2]

The application of the principles of mechanics to soils was documented as early as 1773 when Charles Coulomb, a physicist and engineer, developed improved methods to determine the earth pressures against military ramparts. Coulomb observed that, at failure, a distinct slip plane would form behind a sliding retaining wall and suggested that the maximum shear stress on the slip plane, for design purposes, was the sum of the soil cohesion, , and friction , where is the normal stress on the slip plane and is the friction angle of the soil. By combining Coulomb's theory with Christian Otto Mohr's 2D stress state, the theory became known as Mohr-Coulomb theory. Although it is now recognized that precise determination of cohesion is impossible because is not a fundamental soil property, the Mohr-Coulomb theory is still used in practice today.[3]

In the 19th century, Henry Darcy developed what is now known as Darcy's Law, describing the flow of fluids in a porous media. Joseph Boussinesq, a mathematician and physicist, developed theories of stress distribution in elastic solids that proved useful for estimating stresses at depth in the ground. William Rankine, an engineer and physicist, developed an alternative to Coulomb's earth pressure theory. Albert Atterberg developed the clay consistency indices that are still used today for soil classification.[1][2] In 1885, Osborne Reynolds recognized that shearing causes volumetric dilation of dense materials and contraction of loose granular materials.

Modern geotechnical engineering is said to have begun in 1925 with the publication of Erdbaumechanik by Karl von Terzaghi, a mechanical engineer and geologist. Considered by many to be the father of modern soil mechanics and geotechnical engineering, Terzaghi developed the principle of effective stress, and demonstrated that the shear strength of soil is controlled by effective stress.[4] Terzaghi also developed the framework for theories of bearing capacity of foundations, and the theory for prediction of the rate of settlement of clay layers due to consolidation.[1][3][5] Afterwards, Maurice Biot fully developed the three-dimensional soil consolidation theory, extending the one-dimensional model previously developed by Terzaghi to more general hypotheses and introducing the set of basic equations of Poroelasticity.

In his 1948 book, Donald Taylor recognized that the interlocking and dilation of densely packed particles contributed to the peak strength of the soil. Roscoe, Schofield, and Wroth, with the publication of On the Yielding of Soils in 1958, established the interrelationships between the volume change behavior (dilation, contraction, and consolidation) and shearing behavior with the theory of plasticity using critical state soil mechanics. Critical state soil mechanics is the basis for many contemporary advanced constitutive models describing the behavior of soil.[6]

In 1960, Alec Skempton carried out an extensive review of the available formulations and experimental data in the literature about the effective stress validity in soil, concrete, and rock in order to reject some of these expressions, as well as clarify what expressions were appropriate according to several working hypotheses, such as stress-strain or strength behavior, saturated or non-saturated media, and rock, concrete or soil behavior.

Roles

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Geotechnical investigation

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Geotechnical engineers investigate and determine the properties of subsurface conditions and materials. They also design corresponding earthworks and retaining structures, tunnels, and structure foundations, and may supervise and evaluate sites, which may further involve site monitoring as well as the risk assessment and mitigation of natural hazards.[7][8]

Geotechnical engineers and engineering geologists perform geotechnical investigations to obtain information on the physical properties of soil and rock underlying and adjacent to a site to design earthworks and foundations for proposed structures and for the repair of distress to earthworks and structures caused by subsurface conditions. Geotechnical investigations involve surface and subsurface exploration of a site, often including subsurface sampling and laboratory testing of retrieved soil samples. Sometimes, geophysical methods are also used to obtain data, which include measurement of seismic waves (pressure, shear, and Rayleigh waves), surface-wave methods and downhole methods, and electromagnetic surveys (magnetometer, resistivity, and ground-penetrating radar). Electrical tomography can be used to survey soil and rock properties and existing underground infrastructure in construction projects.[9]

Surface exploration can include on-foot surveys, geologic mapping, geophysical methods, and photogrammetry. Geologic mapping and interpretation of geomorphology are typically completed in consultation with a geologist or engineering geologist. Subsurface exploration usually involves in-situ testing (for example, the standard penetration test and cone penetration test). The digging of test pits and trenching (particularly for locating faults and slide planes) may also be used to learn about soil conditions at depth. Large-diameter borings are rarely used due to safety concerns and expense. Still, they are sometimes used to allow a geologist or engineer to be lowered into the borehole for direct visual and manual examination of the soil and rock stratigraphy.

Various soil samplers exist to meet the needs of different engineering projects. The standard penetration test, which uses a thick-walled split spoon sampler, is the most common way to collect disturbed samples. Piston samplers, employing a thin-walled tube, are most commonly used to collect less disturbed samples. More advanced methods, such as the Sherbrooke block sampler, are superior but expensive. Coring frozen ground provides high-quality undisturbed samples from ground conditions, such as fill, sand, moraine, and rock fracture zones.[10]

Geotechnical centrifuge modeling is another method of testing physical-scale models of geotechnical problems. The use of a centrifuge enhances the similarity of the scale model tests involving soil because soil's strength and stiffness are susceptible to the confining pressure. The centrifugal acceleration allows a researcher to obtain large (prototype-scale) stresses in small physical models.

Foundation design

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The foundation of a structure's infrastructure transmits loads from the structure to the earth. Geotechnical engineers design foundations based on the load characteristics of the structure and the properties of the soils and bedrock at the site. Generally, geotechnical engineers first estimate the magnitude and location of loads to be supported before developing an investigation plan to explore the subsurface and determine the necessary soil parameters through field and lab testing. Following this, they may begin the design of an engineering foundation. The primary considerations for a geotechnical engineer in foundation design are bearing capacity, settlement, and ground movement beneath the foundations.[11]

Earthworks

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A compactor/roller operated by U.S. Navy Seabees

Geotechnical engineers are also involved in the planning and execution of earthworks, which include ground improvement,[11] slope stabilization, and slope stability analysis.

Ground improvement

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Various geotechnical engineering methods can be used for ground improvement, including reinforcement geosynthetics such as geocells and geogrids, which disperse loads over a larger area, increasing the soil's load-bearing capacity. Through these methods, geotechnical engineers can reduce direct and long-term costs.[12]

Slope stabilization

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Simple slope slip section.

Geotechnical engineers can analyze and improve slope stability using engineering methods. Slope stability is determined by the balance of shear stress and shear strength. A previously stable slope may be initially affected by various factors, making it unstable. Nonetheless, geotechnical engineers can design and implement engineered slopes to increase stability.

Slope stability analysis
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Stability analysis is needed to design engineered slopes and estimate the risk of slope failure in natural or designed slopes by determining the conditions under which the topmost mass of soil will slip relative to the base of soil and lead to slope failure.[13] If the interface between the mass and the base of a slope has a complex geometry, slope stability analysis is difficult and numerical solution methods are required. Typically, the interface's exact geometry is unknown, and a simplified interface geometry is assumed. Finite slopes require three-dimensional models to be analyzed, so most slopes are analyzed assuming that they are infinitely wide and can be represented by two-dimensional models.

Sub-disciplines

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Geosynthetics

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A collage of geosynthetic products.

Geosynthetics are a type of plastic polymer products used in geotechnical engineering that improve engineering performance while reducing costs. This includes geotextiles, geogrids, geomembranes, geocells, and geocomposites. The synthetic nature of the products make them suitable for use in the ground where high levels of durability are required. Their main functions include drainage, filtration, reinforcement, separation, and containment.

Geosynthetics are available in a wide range of forms and materials, each to suit a slightly different end-use, although they are frequently used together. Some reinforcement geosynthetics, such as geogrids and more recently, cellular confinement systems, have shown to improve bearing capacity, modulus factors and soil stiffness and strength.[14] These products have a wide range of applications and are currently used in many civil and geotechnical engineering applications including roads, airfields, railroads, embankments, piled embankments, retaining structures, reservoirs, canals, dams, landfills, bank protection and coastal engineering.[15]

Offshore

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Platforms offshore Mexico.

Offshore (or marine) geotechnical engineering is concerned with foundation design for human-made structures in the sea, away from the coastline (in opposition to onshore or nearshore engineering). Oil platforms, artificial islands and submarine pipelines are examples of such structures.[16]

There are a number of significant differences between onshore and offshore geotechnical engineering.[16][17] Notably, site investigation and ground improvement on the seabed are more expensive; the offshore structures are exposed to a wider range of geohazards; and the environmental and financial consequences are higher in case of failure. Offshore structures are exposed to various environmental loads, notably wind, waves and currents. These phenomena may affect the integrity or the serviceability of the structure and its foundation during its operational lifespan and need to be taken into account in offshore design.

In subsea geotechnical engineering, seabed materials are considered a two-phase material composed of rock or mineral particles and water.[18][19] Structures may be fixed in place in the seabed—as is the case for piers, jetties and fixed-bottom wind turbines—or may comprise a floating structure that remains roughly fixed relative to its geotechnical anchor point. Undersea mooring of human-engineered floating structures include a large number of offshore oil and gas platforms and, since 2008, a few floating wind turbines. Two common types of engineered design for anchoring floating structures include tension-leg and catenary loose mooring systems.[20]

Observational method

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First proposed by Karl Terzaghi and later discussed in a paper by Ralph B. Peck, the observational method is a managed process of construction control, monitoring, and review, which enables modifications to be incorporated during and after construction. The method aims to achieve a greater overall economy without compromising safety by creating designs based on the most probable conditions rather than the most unfavorable.[21] Using the observational method, gaps in available information are filled by measurements and investigation, which aid in assessing the behavior of the structure during construction, which in turn can be modified per the findings. The method was described by Peck as "learn-as-you-go".[22]

The observational method may be described as follows:[22]

  1. General exploration sufficient to establish the rough nature, pattern, and properties of deposits.
  2. Assessment of the most probable conditions and the most unfavorable conceivable deviations.
  3. Creating the design based on a working hypothesis of behavior anticipated under the most probable conditions.
  4. Selection of quantities to be observed as construction proceeds and calculating their anticipated values based on the working hypothesis under the most unfavorable conditions.
  5. Selection, in advance, of a course of action or design modification for every foreseeable significant deviation of the observational findings from those predicted.
  6. Measurement of quantities and evaluation of actual conditions.
  7. Design modification per actual conditions

The observational method is suitable for construction that has already begun when an unexpected development occurs or when a failure or accident looms or has already happened. It is unsuitable for projects whose design cannot be altered during construction.[22]

See also

[edit]
  • Civil engineering
  • Deep Foundations Institute
  • Earthquake engineering
  • Earth structure
  • Effective stress
  • Engineering geology
  • Geological Engineering
  • Geoprofessions
  • Hydrogeology
  • International Society for Soil Mechanics and Geotechnical Engineering
  • Karl von Terzaghi
  • Land reclamation
  • Landfill
  • Mechanically stabilized earth
  • Offshore geotechnical engineering
  • Rock mass classifications
  • Sediment control
  • Seismology
  • Soil mechanics
  • Soil physics
  • Soil science

 

Notes

[edit]
  1. ^ a b c d Das, Braja (2006). Principles of Geotechnical Engineering. Thomson Learning.
  2. ^ a b Budhu, Muni (2007). Soil Mechanics and Foundations. John Wiley & Sons, Inc. ISBN 978-0-471-43117-6.
  3. ^ a b Disturbed soil properties and geotechnical design, Schofield, Andrew N., Thomas Telford, 2006. ISBN 0-7277-2982-9
  4. ^ Guerriero V., Mazzoli S. (2021). "Theory of Effective Stress in Soil and Rock and Implications for Fracturing Processes: A Review". Geosciences. 11 (3): 119. Bibcode:2021Geosc..11..119G. doi:10.3390/geosciences11030119.
  5. ^ Soil Mechanics, Lambe, T.William and Whitman, Robert V., Massachusetts Institute of Technology, John Wiley & Sons., 1969. ISBN 0-471-51192-7
  6. ^ Soil Behavior and Critical State Soil Mechanics, Wood, David Muir, Cambridge University Press, 1990. ISBN 0-521-33782-8
  7. ^ Terzaghi, K., Peck, R.B. and Mesri, G. (1996), Soil Mechanics in Engineering Practice 3rd Ed., John Wiley & Sons, Inc. ISBN 0-471-08658-4
  8. ^ Holtz, R. and Kovacs, W. (1981), An Introduction to Geotechnical Engineering, Prentice-Hall, Inc. ISBN 0-13-484394-0
  9. ^ Deep Scan Tech (2023): Deep Scan Tech uncovers hidden structures at the site of Denmark's tallest building.
  10. ^ "Geofrost Coring". GEOFROST. Retrieved 20 November 2020.
  11. ^ a b Han, Jie (2015). Principles and Practice of Ground Improvement. Wiley. ISBN 9781118421307.
  12. ^ RAJU, V. R. (2010). Ground Improvement Technologies and Case Histories. Singapore: Research Publishing Services. p. 809. ISBN 978-981-08-3124-0. Ground Improvement – Principles And Applications In Asia.
  13. ^ Pariseau, William G. (2011). Design analysis in rock mechanics. CRC Press.
  14. ^ Hegde, A.M. and Palsule P.S. (2020), Performance of Geosynthetics Reinforced Subgrade Subjected to Repeated Vehicle Loads: Experimental and Numerical Studies. Front. Built Environ. 6:15. https://www.frontiersin.org/articles/10.3389/fbuil.2020.00015/full.
  15. ^ Koerner, Robert M. (2012). Designing with Geosynthetics (6th Edition, Vol. 1 ed.). Xlibris. ISBN 9781462882892.
  16. ^ a b Dean, E.T.R. (2010). Offshore Geotechnical Engineering – Principles and Practice. Thomas Telford, Reston, VA, 520 p.
  17. ^ Randolph, M. and Gourvenec, S., 2011. Offshore geotechnical engineering. Spon Press, N.Y., 550 p.
  18. ^ Das, B.M., 2010. Principles of geotechnical engineering. Cengage Learning, Stamford, 666 p.
  19. ^ Atkinson, J., 2007. The mechanics of soils and foundations. Taylor & Francis, N.Y., 442 p.
  20. ^ Floating Offshore Wind Turbines: Responses in a Sea state – Pareto Optimal Designs and Economic Assessment, P. Sclavounos et al., October 2007.
  21. ^ Nicholson, D, Tse, C and Penny, C. (1999). The Observational Method in ground engineering – principles and applications. Report 185, CIRIA, London.
  22. ^ a b c Peck, R.B (1969). Advantages and limitations of the observational method in applied soil mechanics, Geotechnique, 19, No. 1, pp. 171-187.

References

[edit]
  • Bates and Jackson, 1980, Glossary of Geology: American Geological Institute.
  • Krynine and Judd, 1957, Principles of Engineering Geology and Geotechnics: McGraw-Hill, New York.
  • Ventura, Pierfranco, 2019, Fondazioni, Volume 1, Modellazioni statiche e sismiche, Hoepli, Milano
[edit]
  • Worldwide Geotechnical Literature Database

 

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USS was excellent. They are honest, straightforward, trustworthy, and conscientious. They thoughtfully removed the flowers and flower bulbs to dig where they needed in the yard, replanted said flowers and spread the extra dirt to fill in an area of the yard. We've had other services from different companies and our yard was really a mess after. They kept the job site meticulously clean. The crew was on time and friendly. I'd recommend them any day! Thanks to Jessie and crew.

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It was a pleasure to work with Rick and his crew. From the beginning, Rick listened to my concerns and what I wished to accomplish. Out of the 6 contractors that quoted the project, Rick seemed the MOST willing to accommodate my wishes. His pricing was definitely more than fair as well. I had 10 push piers installed to stabilize and lift an addition of my house. The project commenced at the date that Rick had disclosed initially and it was completed within the same time period expected (based on Rick's original assessment). The crew was well informed, courteous, and hard working. They were not loud (even while equipment was being utilized) and were well spoken. My neighbors were very impressed on how polite they were when they entered / exited my property (saying hello or good morning each day when they crossed paths). You can tell they care about the customer concerns. They ensured that the property would be put back as clean as possible by placing MANY sheets of plywood down prior to excavating. They compacted the dirt back in the holes extremely well to avoid large stock piles of soils. All the while, the main office was calling me to discuss updates and expectations of completion. They provided waivers of lien, certificates of insurance, properly acquired permits, and JULIE locates. From a construction background, I can tell you that I did not see any flaws in the way they operated and this an extremely professional company. The pictures attached show the push piers added to the foundation (pictures 1, 2 & 3), the amount of excavation (picture 4), and the restoration after dirt was placed back in the pits and compacted (pictures 5, 6 & 7). Please notice that they also sealed two large cracks and steel plated these cracks from expanding further (which you can see under my sliding glass door). I, as well as my wife, are extremely happy that we chose United Structural Systems for our contractor. I would happily tell any of my friends and family to use this contractor should the opportunity arise!

Chris Abplanalp

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USS did an amazing job on my underpinning on my house, they were also very courteous to the proximity of my property line next to my neighbor. They kept things in order with all the dirt/mud they had to excavate. They were done exactly in the timeframe they indicated, and the contract was very details oriented with drawings of what would be done. Only thing that would have been nice, is they left my concrete a little muddy with boot prints but again, all-in-all a great job

Dave Kari

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What a fantastic experience! Owner Rick Thomas is a trustworthy professional. Nick and the crew are hard working, knowledgeable and experienced. I interviewed every company in the area, big and small. A homeowner never wants to hear that they have foundation issues. Out of every company, I trusted USS the most, and it paid off in the end. Highly recommend.

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