119 Design and Application of Prestress Drill-Grouted Diaphragm Wall in the Foundation Pit Bracing

Prestress drill-grouted diaphragm wall, which mainly based on the mechanism of Soil Mixing Wall (SMW) and prestressing technique, is presented. It is grouted the drill-hole with discard drilling slurry, cement and admixture fly ash at a fixed rate. After grouting, insert shaped-steel in it and form the mixing wall, then choose the prestressed anchor or bolting support according to the condition of soil and foundation pit structure. The design theory of m method is provided to calculate the earth pressure, displacement and bending moment of the wall. Combined the unconfined compressive strength test of cement-soil, the bracing design of foundation pit is presented. With the successful application in the foundation treatment in Wuhan, China, the practicality and use for reference of this technique and monitoring data of the wall prove that it could be used in the similar engineering owing to such characteristics as high strength, low cost, environment protection and so on.