The Simulation Test Research Of Soil Nailing Support Structurewith Prestressed Anchor Of Deep Excavation Engineering

With the rapid development of city construction, appearing a large number of deepfoundation pit engineering.Soil nailing support for economic, reliable and fast construction,has been popularized and applied rapidly in our country in the foundation pit excavation. Butbecause of the need to be allowed to set soil nailing of underground space, in the loose sand,soft soil, plastic flow under the condition of cohesive soil and groundwater is rich can’tseparate use of soil nailing and other shortcomings, the composite soil nail supportingtechnology appears. Composite soil nailing supporting technology is based on the soil nailingmainly, complementary with other reinforcement measures to maintain and improve the slopestability of the composite support method.The paper researches on bolt supporting of foundation pit considering constructionprocess，considering different lengths in the foundation pit engineering configuration methodof soil nailing. A homogeneous soil foundation pit is set up firstly in the stimulation test, thenexcavating the foundation pit and soil nailing construction. Through the analysis of test datato draw the conclusion: Each step excavation has a corresponding potential slip surface,discussed from the aspects of local stability, each row of a maximum length of soil nail designalso need to guarantee the stability of corresponding soil collapse collapse section, after theexcavation to the next layer, excavation can form new potential slip surface, thecorresponding layer soil nail to make this part of the soil mass stability, at the same time in arow soil nail pull-out force are also provided. Through experiments it is concluded that theoptimal way of soil nailing arrangement, at the same time expanding the configuration modeof soil nailing support structure with prestressed anchor.On the basis of indoor test, combined with a practical engineering of deep foundation pit, using the numerical simulation of MIDAS/GTS, further, studying prestressed anchor workand the mechanism of compound soil nailing support are obtained following conclusions:(1) The soil nail axial force distribution shape presents the central large, upper and lowerends of the small.(2) In construction process of prestressed anchor composite soil nailing support scheme,because the anchor prestress effect, adjacent anchor soil nailing internal force obviously onthe low side, close to anchor the soil nail reinforcement role not into full play.(3) In practical engineering, according to the result of finite element analysis, areasonable adjustment to prestressed anchor length of soil nail, so as to improve theeffectiveness of the soil nailing using.