地下连续墙-桩组合基础的水平承载性能

地下连续墙-桩组合基础是将地下连续墙与桩基础结合的一种新型变刚度基础形式。从设计理念上讲，地下连续墙-桩组合基础具有较好的抵抗侧向变形的能力且兼具经济型，然而目前还缺乏从受力特性角度对该新型基础形式的受力机理进行系统的研究。基于开展的大比尺现场模型试验真实模拟新型组合基础在水平荷载下的受力，将试验和数值模拟结果对比得出基础的荷载与位移的变化规律。通过分析不同等级荷载下组合基础的变形特性，揭示基础的荷载传递规律，并对桩墙组合基础的水平承载力进行了初步近似计算。结果表明：水平荷载作用下组合基础出现整体倾斜破坏；墙身弯矩远大于桩身弯矩，桩墙弯矩随加载等级的递增而逐渐增大，且弯矩最大处位置与弯矩峰值位置不变；随埋深、荷载的增加，墙侧土压力呈现非线性变化，地连墙边侧土压力大于中间土压力，并且最大土压力出现在连续墙中下部。

Study on Horizontal Bearing Capacity of Diaphragm Wall-Pile Composite Foundation

The underground diaphragm wall-pile composite foundation is a new type of variable rigidity foundation which combines diaphragm wall with pile foundation. From the design concept, the combination of underground diaphragm wall-pile foundation has a better ability to resist lateral deformation and both economic. However, there is still a lack of systematic research on the mechanism of this new type of foundation from the perspective of mechanical characteristics. Based on the large-scale field model test conducted to truly simulate the stress of the new composite foundation under horizontal load, the load and displacement variation rules of the foundation are obtained by comparing the test and numerical simulation results. Analyzing the deformation characteristics of composite foundation under different load levels reveals the law of load transfer. And the preliminary approximate calculation of the horizontal bearing capacity of the combined pile-wall foundation is carried out. The results show that: the composite foundation under horizontal load has been inclined to failure as a whole; the bending moment of the wall is much larger than that of the pile, the bending moment of the pile wall increases gradually with the increase of the loading grade, and the position of the maximum bending moment as well as the peak bending moment remain unchanged; and with the increase of burial depth and load, the earth pressure on the wall side presents a non-linear change, the earth pressure on the side of the underground diaphragm wall is greater than that on the middle, and the maximum earth pressure appears in the middle and lower part of the underground diaphragm wall.