Research On Double-row-pile Composite Soil Nailing In Soft Foundation Pit Support

Double-row-pile composite soil nailing(DPCSN) is a new bracing structure of foundation pit.In recent years, DPCSN has been used in the region of Hangzhou,Shaoxing and so on,obtaining good economic and social performance.But up to now,work mechanism and stability study of DPCSN is a blank.There are no calculation analysis methods for DPCSN and the design of it mainly depends on experience.The behind schedule theories research make further development of DPCSN limited.Based on the soil nailing and compound soil nailing research,according to DPCSN present research condition and effective demand of the engineering,the stability of DPCSN is studied by methods of traditional theories research , field testing data research, engineering case research and Plaxis finite element programming research.Some beneficial results of the mechanism and behaviors of DPCSN are gotten.Main research contents as follows:(1) Origin and development of DPCSN are introduced.The advantage and the limitation of DPCSN are pointed out.(2) The conformation craft, construction organization of DPCSN,the measure of foundation pit safety and quantity guarantee are summarized.(3) Studying the work mechanism of DPCSN,the model of stability analysis of DPCSN is established.(4) According to related standards,the model of DPCSN is examined by computation and analysis of engineering case and is modified.(5) Computation of engineering case model building used by Plaxis finite element programming,combining field testing data and other bracing structures,makes data of sress and strain analysed and compared,further verifying the stability of DPCSN.