为使无杆钻具能有效支撑在孔壁土体上,探讨了支护结构施加的预应力对孔壁土体稳定性的影响,提出了采用虚拟土柱模拟桩孔并结合广义Mindlin解的方法,推导了预应力作用下孔壁土体中任一点的附加应力向量.基于此附加应力向量,求取了最大预...为使无杆钻具能有效支撑在孔壁土体上,探讨了支护结构施加的预应力对孔壁土体稳定性的影响,提出了采用虚拟土柱模拟桩孔并结合广义Mindlin解的方法,推导了预应力作用下孔壁土体中任一点的附加应力向量.基于此附加应力向量,求取了最大预扭矩和最大预压力作用下支护板下方5 mm、宽50 mm处各点的剪切应力及其相对强度.结果表明:当预扭矩与预应力分别为120 k N·m和100 k N时,最大剪切应力为6.52 MPa;除了支护板两端部外,剪切应力相对强度均小于1,即总体上孔壁土体为稳定状态.与试验结果的对比验证了文中方法的正确性。展开更多
A new approach is proposed to analyze the settlement behavior for single pile embedded in layered soils. Firstly, soil layers surrounding pile shaft are simulated by using distributed Voigt model, and finite soil laye...A new approach is proposed to analyze the settlement behavior for single pile embedded in layered soils. Firstly, soil layers surrounding pile shaft are simulated by using distributed Voigt model, and finite soil layers under the pile end are assumed to be virtual soil-pile whose cross-section area is the same as that of the pile shaft. Then, by means of Laplace transform and impedance function transfer method to solve the static equilibrium equation of pile, the analytical solution of the displacement impedance fimction at the pile head is derived. Furthermore, the analytical solution of the settlement at the head of single pile is theoretically derived by virtue of convolution theorem. Based on these solutions, the influences of parameters of soil-pile system on the settlement behavior for single pile are analyzed. Also, comparison of the load-settlement response for two well-instrumented field tests in multilayered soils is given to demonstrate the effectiveness and accuracy of the proposed approach. It can be noted that the presented solution can be used to calculate the settlement of single pile for the preliminary design of pile foundation.展开更多
文摘为使无杆钻具能有效支撑在孔壁土体上,探讨了支护结构施加的预应力对孔壁土体稳定性的影响,提出了采用虚拟土柱模拟桩孔并结合广义Mindlin解的方法,推导了预应力作用下孔壁土体中任一点的附加应力向量.基于此附加应力向量,求取了最大预扭矩和最大预压力作用下支护板下方5 mm、宽50 mm处各点的剪切应力及其相对强度.结果表明:当预扭矩与预应力分别为120 k N·m和100 k N时,最大剪切应力为6.52 MPa;除了支护板两端部外,剪切应力相对强度均小于1,即总体上孔壁土体为稳定状态.与试验结果的对比验证了文中方法的正确性。
基金Project(50879077) supported by the National Natural Science Foundation of China
文摘A new approach is proposed to analyze the settlement behavior for single pile embedded in layered soils. Firstly, soil layers surrounding pile shaft are simulated by using distributed Voigt model, and finite soil layers under the pile end are assumed to be virtual soil-pile whose cross-section area is the same as that of the pile shaft. Then, by means of Laplace transform and impedance function transfer method to solve the static equilibrium equation of pile, the analytical solution of the displacement impedance fimction at the pile head is derived. Furthermore, the analytical solution of the settlement at the head of single pile is theoretically derived by virtue of convolution theorem. Based on these solutions, the influences of parameters of soil-pile system on the settlement behavior for single pile are analyzed. Also, comparison of the load-settlement response for two well-instrumented field tests in multilayered soils is given to demonstrate the effectiveness and accuracy of the proposed approach. It can be noted that the presented solution can be used to calculate the settlement of single pile for the preliminary design of pile foundation.
