复合地基沉降计算的半解析元法  

Semi-analytical element method of settlement computation for composite foundation

作　　者：刘丽萍[1] 黄义[2] 李向阳[3] 刘增荣[1] 

机构地区：[1]西安建筑科技大学土木工程学院,西安710055 [2]西安建筑科技大学理学院,西安710055 [3]同济大学地下建筑与工程系,上海200092

出　　处：《岩土力学》2006年第10期1685-1688,1692,共5页Rock and Soil Mechanics

基　　金：陕西省教育厅专项基金资助项目(No.03JK136)。

摘　　要：将复合地基视为横观各向同性体,利用半解析数值计算原理,又将复合地基位移竖向离散为多项式,在水平两个方向上选取解析函数模拟无限域地基进行计算,从而克服了有限元计算中人为设定计算边界的弊端,提高了计算精度,并将三维沉降问题转化为一维问题进行计算,收敛速度快,显著地减少了计算工作量,将计算结果与理论解进行对比,满足精度要求。通过改变复合地基置换率、加固深度和桩土模量比,采用半解析元法研究了复合地基的加固效果,计算结果表明,桩土模量比较大时,可忽略加固区压缩变形量;增大置换率对减小沉降作用很小,而增加加固深度能明显减小复合地基沉降,在以控制沉降量为主要目的复合地基优化设计中应首先考虑增加加固深度。Based on the principle of semi-analytical method and the assumption of transversely isotropic material of composite foundation, a semi-analytical element method has been presented to calculate the settlement of composite foundation. Vertical displacement is discretized as polynomial expressions, and horizontal displacements are modeled by means of displacement functions in two directions to simulate infinite field. For one direction discrete and two directions analytical, this method can simplify 3-dimensional computation of displacements into one dimension, it can save computation time dramatically for its quick convergence Furthermore it can simulate infinite soil field and acquire precise results for avoiding introduce redundant boundary condition compared with FEM, An example has been calculated with semi-analytical element method by changing substitution ratio, improved depth and modulus ratio of pile to soil of composite foundation. The results indicate that the substitution ratio and the modulus ratio of pile to soil have little effect on reducing displacement; while increasing improved depth can affect settlement obviously. So it is reasonable to increase improved depth to reduce composite foundation settlement under the circumstance that the optimum design is controlled by ground settlement.

关 键 词：半解析有限元 复合地基 沉降计算 

分 类 号：TU472.2[建筑科学—结构工程]