Foundation Pit Support Of Cement Soil Stirred å·¥ Pile Used In Silt Sand

When it is used in silt sand deep foundation, foundation pit support technology that implants I-shaped reinforced concrete pile after cement mixes with soil exists such questions as slow drill footage, big drill wear, quick cement slurry solidification, hard control of pile verticality. This paper achieved the method of drilling rig using and designed the drill and drilling rig parameters in silt sand, through comparison with rock and soil drilling and excavation joining with drill development home and abroad, researching engineering behavior of silt sand. It also made optimum design of spiral drill, improved the parameters of spiral drill in condition of maximum transportation capacity. When it was used in deep foundation, it needs to joint pile. The mixed soil cement should not develop to solidification after the joint and press of pile. This research added bentonite and sucrose retarder in traditional SMW construction method to control the setting time and uniformity of soil cement. It tested the setting time of soil cement which contained bentonite and sucrose retarder, and the cement setting time test instrument was used as the relative standard. The effect of sucrose retarder content on the cement soil's unconfined compressive strength was investigated. The reasonable proportional parameters were identified. The test results was verified in the project of Hangzhou Economic and Technological Development Zone C4-3-9 Block foundation support which contains silt sand. This paper proved that these parameters could solve the problems in silt sand, improve the stability,water retention,dispersion and uniformity of cement slurry, and guarantee the joint, press and strength of pile. This method expanded the range of foundation pit support technology that implants I-shaped reinforced concrete pile after cement mixes with soil, and supplied references for similar projects.