Earth Retention
Earth Retention systems are constructed to provide excavation shoring and support, and to mitigate slope instability. Earth retention systems can have permanent service lives, or only provide temporary shoring during construction activities. The design and construction of earth retention systems must consider stabilizing lateral earth pressures, controlling movement, and draining potential water pressure.
Drill Tech Drilling & Shoring, Inc. designs and builds earth retention systems for numerous applications
including excavation shoring, landslide mitigation, and permanent/temporary retaining walls. We routinely utilize soil nail walls, soldier pile walls, tieback anchors, sheet pile walls, and cutter soil mixing for these applications.
Soil Nail Walls
Drill Tech has been an innovator in soil nail design and construction for geotechnical construction in the western United States for over 20 years. Our custom-built drill rigs consistently outperform our competition, allowing for faster and more cost-efficient design and construction of permanent and temporary soil nail walls. On average, Drill Tech constructs approximately 1,000,000 SF of soil nail walls each year.
Drill Tech’s staff of professional engineers has designed over 1,000 soil nail walls.
Our professional engineers and project managers have developed working relationships with countless cities, counties, developers, and government agencies to facilitate the review and approval process.
The concept of soil nailing is to reinforce and strengthen an existing ground mass by installing closely spaced horizontal ground anchors (soil nails).
Soil nail walls are typically constructed in stages from the top down in “cut wall” applications, and are feasible in virtually any dewatered ground condition. Drill Tech has installed soil nail walls ranging in height from five feet to in excess of 130 feet tall. Soil nailing can be used for permanent retaining walls as well as temporary shoring. The shotcrete facing may then be finished in a variety of ways, including being sculpted and stained to resemble natural rock, or creating a smooth trowel flat finish.
Excavation Shoring 
Road & Highway Retaining Walls
Bridge Abutment Retaining Walls
Slope & Landslide Stabilization
New Construction Site Walls
Existing Retaining Wall Retrofits
Tunnel Portal Shoring
tieback anchors
Drill Tech Drilling & Shoring, Inc. is an industry leader in ground anchor solutions. Our ground anchor drill rig fleet consists of several dozen machines, including conventional Klemm 803, 806 and 807 tieback machines, an 80-foot stroke “rocket launcher” drill, and custom-built, excavator- and forklift-mounted, crane-suspended drill basket platforms. Drill Tech Drilling has successfully installed ground anchors in every imaginable type of ground, with design loads in excess of 2,000 kips and lengths in excess of 300 feet.
The steel tendons have a free stressing (unbonded) length and a bonded length.
The bonded portion of a tieback is the length of the tendon bonded to the anchor grout and transmits the applied tensile load into the ground. The unbonded length is the portion of the tendon that is free to elongate and transfer the resisting force from the bond length to the anchorage. Tieback anchors can be corrosion protected with epoxy coating or corrugated plastic sheathing to provide a permanent service life. For temporary shoring applications, bare strand or bar can be used.
Soldier Pile Retaining Structures and Shoring Systems
Slope and Landslide Stabilization
Anchored Shoring Systems Including CSM, Sheet Piles, and Secant Piles
Rock Anchors
Existing Retaining Wall Retrofits
Additional Lateral Support for New Foundations
cutter soil mixing (CSM)
Drill Tech is continually at the forefront of the geotechnical construction industry, utilizing innovative new technologies for earth retention and ground treatment. Over the past 15 years, Drill Tech has expended a tremendous amount of time and effort to further develop the use of the cutter soil mix method for earth retention and ground treatment needs.
For earth retention applications, cutter soil mixing (CSM) is a method of constructing an impermeable retaining system by mixing native soils with cement and/or bentonite grout.
A continuous wall is formed by overlapping a series of rectangular soil mix panels. The panels are typically reinforced with steel beams for structural purposes. CSM is mainly used for stabilizing soft or loose soils. However, the cutter technology extends the applicability of the method to much harder strata when compared to other methods of soil mixing.
For non-earth retention applications, CSM is used to improve the characteristics of the in-situ soil, resulting in higher compressive strengths and lower permeability.
Typically, every second shaft is reinforced with a steel beam or reinforcing cage and the intermediate shafts are filled with lean concrete. When secant piles are used to shore a circular shaft excavation, vertical steel reinforcement is typically unnecessary, because the secant piles form a concrete compression ring.
CSM is used as a ground improvement method to create homogeneous foundation support and increased bearing capacity, and to mitigate liquefiable soils. CSM can also be used as a barrier to contain the migration of underground contaminants.
Native soils are used as the construction material
Can be used in very dense soils and weathered bedrock
Minimal generation of spoils
No vibrations and little noise during construction
Cut-off walls
Excavation shoring in saturated and loose soil conditions
Shaft construction
Foundation support
Liquefaction mitigation
soldier pile walls
Drill Tech has installed over 1,000,000 square feet of soldier pile retaining walls, using both driven and drilled beams, with and without tiebacks. Soldier pile walls provide support through the stiffness of the steel beams supported by the ground below the finished grade. They are effective earth retention systems in both “fill” and “cut” wall situations and are especially useful along property boundaries. Soldier pile systems can be used as permanent retaining walls and as temporary shoring.
Soldier pile walls consist of soldier pile beams (steel HP or W sections) that are vertically driven or concreted into drilled holes.
Excavation Shoring and Underpinning
Road and Highway Retaining Walls
Slope and Landslide Stabilization
New Construction Site Walls
Cut and Cover Tunnel Walls
secant pile walls
Secant pile walls provide a deep foundation cutoff system and lateral support through overlapping drilled shafts that form a continuous wall.
Secant pile walls are effective at retaining saturated soils and preventing water seepage and loss of retained soil during excavation.
Typically, every second shaft is reinforced with a steel beam or reinforcing cage and the intermediate shafts are filled with lean concrete. When secant piles are used to shore a circular shaft excavation, vertical steel reinforcement is typically unnecessary, because the secant piles form a concrete compression ring.
Excavation shoring in saturated and loose soil conditions
Shaft construction
Cut-off walls
sheet pile walls
Drill Tech is constantly adapting to meet shoring needs for any soil type or project need. Our state-of-the-art fleet of construction equipment can vibrate or press sheet piles up to 80 feet in one continuous stroke. Drill Tech has driven sheet pile walls for various projects ranging from cofferdams in a riverbed to temporary shoring for pipeline construction.
Sheet pile walls provide retention support through the stiffness of continuous vertical wall elements and passive resistance from the ground below the finished grade.
They are an effective shoring system which retains both earth and water.
Sheet pile walls consist of interlocking steel members, typically “Z” shaped, vertically driven or vibrated to a determined depth below the base of the retained material.
Excavation shoring
Retaining soils below the water table
Cut-off walls
Cofferdams