Arched Baffle-pile Anchor Support Strucutre Model Test And Research On Vertical Soil Arch Effects

The pile-anchor retaining structure is still one of the most widely used support formin excavation engineering at present, and at design phase it’s usually the classical earthpressure theory to calculate the earth pressure behind the piles. Numerous field testsshowed that the actual earth pressure distribution displays non-linear under the influenceof the support form, soil properties and soil arching effect. The earth pressurecalculation method for supporting structure needs urgent correction. Affected byblocking effect of the supporting structure, soil outside the foundation deform uneven,vertical soil arch effect emerges above the bolt, which has an important impact on theearth pressure transmission and distribution. As a result, analysis of vertical soil archinghas engineering significance for earth pressure calculation and correction.To solve these problems, the following work is carried out: employ model testmethod to monitor the distribution of soil stress field, deformation and the forces ofsupporting structure under different operation conditions. Making use oftwo-dimensional finite difference program to establish foundation pit engineering model,analyze the soil stress distribution behind the retaining pile. Based on vertical soilarching, applying oblique soil element method, the soil stress distribution formulabehind piles is derived.Earth stress and pile deformation are monitored during the indoor model test. Soilgravity stress curves present attenuation between two anchor layers and lateral soilpressure distribution appears relative peak point at the fulcrum of the bolt, whichproves that vertical soil arch is formed up here at the bolt. It significantly affects thesoil stress redistribution. The displacement contrast between supporting piles andarched baffle shows that the vaulted baffle owns arch space effect, and thus has arelatively smaller displacement than usual pile-anchor structure, which proves itsstructure superiority. Through two-dimensional model computation, there is anobvious deflection above bolts, which appears asymmetrical arch distribution. Archaxis and boundary points are confirmed according to principal stress difference curve. Based on vertical soil arch, the oblique soil element earth pressure method has higheraccuracy, and the earth pressure distribution curve confirms to test results with certainaccuracy.