Deformation Response Analysis Of Expensive Soil Foundation PIT Slope Under Different Supporting Structure

A variety range of supporting structure and complex support system has been widely employed in expansive soil foundation pit engineering at the present stage. A large number of engineering practice shows that some of the support structures such as cantilever piles lead to the damage of engineering because of inability to effectively support expansive soil slope deformation, while others such as pile-anchor supporting and double-row-piles would increase the cost as a result of unclear understanding of its supporting effect though they can ensure the safety.To discuss the deformation control effect of different supporting structure in ordinary expansive soil foundation pit, the article first created four different supporting structure numerical models in same boundary condition to study by considering economy and construction conditions. Then the author select different supporting structure of an expansive soil foundation pit in the eastern suburbs of Chengdu for study. It obtained the expansive soil foundation pit slope’s horizontal displacement under different supporting structure by field test. To study the expansive soil foundation pit slope’s deformation response and influence factor under different supporting structure which include pile-anchor, double-row-piles, pile-anchor-bracing and double-row-piles-bracing, the article create four numerical models of different supporting structure on the basis of foundation pit test to calculate. Then take the calculated results to compare with the test results. The article analyzed the cause of failure of double-row-piles-bracing by using the methods of field study, laboratory experiments and numerical simulation.The analysis results show that:The article recommends double-row-piles support in general deep expansive soil pit engineering for the limitation of economy and construction conditions, though both the double-row-piles and double-row-piles-bracing supports are little in the response of deformation. Pile-anchor support can effectively control the expansive soil pit slope deformation rate in the excavation and rainfall conditions because of the application of anchor. Due to the strong stiffness, the degree of deformation about double-row-piles support is less than pile-anchor support.The application of bracing can control the continued deformation of expansive soil pit slope effectually.