Application Research On The Supporting Structure Consist Of Single Row Pile And Anti-draw Anchor Pipe In Soft Soil Pit

With the rapid development of cities, the requirement on the number of the underground garage is increasing, and the design of connected underground garage become a popular trend. In addition, the requirement of the residents on the area's green space are also increasing, which need nearly 1m thick layer of soil on the underground garage to the green design, coupled with top and bottom of the thickness of the underground garage, the depth of the pit is very easy to over 6m, to the range of deep foundation. The anchor in soft ground segment can not play the anchoring role, and making holes for soil nailing in soft soil is difficult, so anchoring pipe nail appears. But the anti-draw force of anchoring pipe nail is not reliable because it has some disadvantages, for example, cement mortar blowing is hard, serosity outflow from near holes, and serosity only surrounds the stock outlet. Therefore inventing an anti-draw structure for soft soil pit has promising prospect. and it's not easy to control the deformation of pit, especially when the edge of pit is near to the range of the red line and load around the pit, temporary facilities and transport add additional stress. Therefore, the development of a more applicable uplift structure of soft soil pit has a good prospect, cement mixing anti-draw anchor pipe is invented under this background, whose appearance solve this problem that the anti-draw force of anti-draw anchor pipe and soil nail is not enough.The composite retaining structure of single row pile-cement mixing anti-draw anchor pipe is a new kind of design method and construction process, had been widely used in Hangzhou, Shaoxing etc south in soft soil area, and achieved good social and economic benefits. Study of cement mixing pile-single anchor pipe resistance to pull pile composite retaining stability and the deformation regularity, has important theoretical significance and practical significance.In this paper, based on the analysis of the supporting mechanism of The composite retaining structure of single row pile-cement mixing anti-draw anchor pipe, considering the force characteristics of the two components, a new computing ideas is presented that the reinforcement and anchoring effect of uplift anchor tube to the active area is equivalent to imposing a certain thickness of the gravity retaining wall. The calculation model analyzing the stability of the retaining wall of anti-capsizal and anti-slip is given. By comparing the calculation results of the projects example and the result of the finite element software, the refering value of this model analyzing forcing mechanism of single row pile-anti-draw anchor tube.In addition, this paper also studies the influencing factors of wording state of the supporting structure, and analyzes all kinds of factors based on the deformation parameters of pit by finite element software Plaxis. This paper mainly reached the following conclusions:(1) the influence of the length of the anchor is large, the horizontal displacement of composite structure is discreasing with the increasing of the length of the anchor. However, when the length is over 18m, the discreasing trend of the maximum horizontal displacement of composite structure is slow with the increasing of the length of the anchor. (2) in soft soil pit, when(?) is certain, the maximum horizontal displacement of pit is firstly sensitive and then insensitive to the change of c with the increasing of c; when c is certain, the maximum horizontal displacement of pit is decreasing continuously and rapidly with the increasing of(?).(3) for the clayey silt soil with c of 8.6KPa and of 4.0°, when the depth of the pit is over 7.5m, the horizontal displacement of pit is large, so the passive area should be reinforced when using the supporting structure.