路堤荷载下双向增强复合地基荷载分担比及沉降计算

针对路堤荷载下双向增强复合地基受力变形特性,以单桩有效影响范围内的路堤与复合地基为分析对象,引入大挠度环形薄板考虑加筋垫层的“柔性筏板效应”与“拉膜效应”,同时通过假定桩土相对位移模式,考虑地基成层性,从而建立了路堤、水平加筋体、桩体、桩间土协调变形三维模型,获得了路堤荷载作用下双向增强复合地基的荷载分担比及沉降计算方法。采用某工程试验数据对该计算方法进行验证,同时分析了路堤高度、桩帽宽度、筋材抗拉模量对中性点位置、桩土差异沉降以及复合薄板中面最大拉应力的影响,结果表明该方法所求得的荷载分担比及沉降与实测值较为接近,证明了其合理性。

Calculation of load sharing ratio and settlement of bidirectional reinforced composite foundation under embankment loads

According to the working characteristics of the bidirectional reinforced composite foundation under embankment loads, the embankment and composite foundation in the equivalent reinforced range of a single pile are regarded as a typical analysis element. The large deflection circular ring thin plate is introduced to simulate the combined effect of “flexible raft” and “tensioned membrane” of the reinforced mattress. And the layered property of the foundation soil is considered based on the assumed model for the relative displacement between the pile and the soil. A mechanical model with consideration of deformation compatibility between the embankment, reinforcement and pile-soil reinforcement area is established based on the above operation, and the methods for calculating the load sharing ratio and settlement are proposed respectively. Field tests are used to verify the proposed method and the influence of the factors such as height of embankment, width of pile cap and tensile modulus of reinforcement on the position of neutral point, differential settlement and maximum tensile stress in the middle plane. The comparative results indicate the proposed method is feasible to be used in the practice.