It used to be that civil engineers and builders were forced to simply work with whatever quality subsoil happened to exist where they planned to build. With the improvement of geotechnical engineering techniques and technologies, this soil can now be amended or modified as needed. These modifications are permanent, and allow the soil to be much more stable and resistant to compressing and permeability among other things. Of course, this requires specialty equipment and processes, as well as tight quality control. Below is a look at a few of the common ways soil improvement and ground stabilization is accomplished.
Slurry and Grout Mixing Plants
Slurry and grout mixing plants come in a range of sizes and capacities depending on a project’s needs. Portable mixers can be mounted on trailers and are ideal for smaller projects. Special mixers exist for special materials like biopolymer slurries, which require pre-mixing the ingredients before they go into the main mixing tank. A flash mixer allows for large amounts of material to be processed into slurry in a short amount of time and is perfect for extensive ground stabilization jobs using bulk materials. There are also slurry mixing plants that allow for highly precise measuring of multiple ingredients on a large scale. These machines can be traditionally controlled or automated, and are available in a range of holding capacities.
Slurry pumps allow for rapid delivery of slurry at varying rates according to need. Some pumps are made to pump the slurry over short distances while others can transport materials to locations up to a mile away. High volume pumps can move large quantities of slurry long distances. The variable speed controls on some pump types help minimize wear and tear to the machines. Transfer pumps move liquid ingredients short distances and are able to load mixers and trucks. Electric pumps offer the benefits of reduced noise and higher accuracy.
Excavator attachments are used in building deep slurry walls. Boom and stick attachments in varying configurations are used for differing depths. Clamshell buckets can dig deeply and do so in tight quarters. Heavy duty clamshell buckets are indispensable for larger jobs, able to dig to depths of 165 feet.
Soil Mixing Equipment
Soil mixing equipment creates stable columns of soil that join together to form barriers, foundation support, and more. Soil mixing attachments act as a drill, boring into the earth. Grout is poured into the space created, then mixed into the soil as the attachment continues to spin while retracting from the earth. Soil mixing rigs can turn sites containing hazardous wastes into large blocks of treated and stabilized soil. Special purpose rigs have the benefit of being easy to move and set up. Unlike crane-operated units, downward-pressure can be applied.
Quality Control Equipment
Quality control is essential for all building projects, and especially projects of this nature. Slurry testing equipment is available to ensure parameters are met. Flow meters measure the flow rates of grout and slurry. Automatic density meters allow monitoring of slurry mix ratios in automated machines. Electronic instruments and controllers are available for most soil stabilization equipment. Field testing equipment makes testing grout and slurry strength easy.