Retain the unstable soil mass with Sinorock soil nails
In many construction projects soil nails are used to retain the unstable soil mass. To accomplish this, soil nails are installed in an evenly spaced close geometric pattern. When installing a soil nail stabilization project, the soil nail installations and the excavation must be accomplished in incremental depths of 1.2m to 1.8m until the final depth of cut is accomplished. Usually only one increment can be completed per day. Immediately following the incremental excavation of the soil and the soil nail installations, the vertical face of the soil is covered with a steel reinforced coating of shotcrete. Soil nails are passive structural elements and are not tensioned after installation. The soil nail gains pullout resistance from within the sliding soil mass in front of the slip plane and the stable soil mass located behind the slip plane. The geometric system of soil nail placements creates an internally reinforced soil mass that is stable. Notice that each soil nail shaft has a great number of helical plates with the same diameter. These helical plates are evenly spaced along the entire length of the shaft. By comparison, a tieback anchor has one or more helical plates situated at the tip of the tieback. These helical plates generally increase in diameter along the shaft away from the tip. Once a tieback anchor lead section is installed, extensions without helical plates are used to extend the helical plates at the tip to the target depth. Soil nails, on the other hand, will always have identical evenly spaced, small diameter helical plates along the entire shaft from beginning to end.
Sinorock were engaged to assist in the investigation and design of the an alternative soil nail excavation support system.
Also, and even though there had been our previous geotechnical investigation at the site using a drilling equipment,Sinorock recommended that additional test pit investigations being carried out as part of the design process, as well as to ensure the safety and stability of the proposed excavations. The result of the additional investigations confirmed Sinorock's initial view that the strength of the strata assessed by the drilling investigation, was in error and that a soil nail method of excavation support would be appropriate.
Subsequently, the excavation was undertaken using the Sinorock recommended approach and completed on time and well under budget. The installed system also embodied a number of unique approaches to the way in which a soil nails are installed that were developed in conjunction between Sinorock engineers and the project builder.