岩质边坡上基桩数值模拟与正交试验设计

目的研究岩质边坡上基桩的受力及变形特性,考虑多种因素的复合作用下基桩的受力及变形的影响.方法结合正交试验设计原理对岩质边坡上桥梁基桩进行设计,并采用大型通用非线性有限元分析软件MSC.Marc对其进行数值模拟,以分析这些因素变化对基桩的变形及受力的影响规律.结果运用正交设计及有限元法得到的结果与一般工程经验相符,具有一定的可靠性.其中各个因素对水平位移的贡献主次顺序为：内摩擦角〉竖向荷载〉均布荷载〉水平荷载〉边坡坡度〉黏聚力〉桩径,而对最大弯矩值的贡献主次关系为：内摩擦角〉桩径〉黏聚力〉边坡坡度〉水平荷载〉均布荷载〉竖向荷载.结论桩周岩体的强度对基桩的位移和内力影响最大,在施工中应尽量保护桩周岩体的完整性和强度.此外,岩质边坡上基桩表现出被动桩的特性,坡顶分布荷载对基桩位移影响也较大,在施工过程中也应尽量避免在坡顶产生较大堆载.

Research of Pile Foundation under Numerical Simulation and Orthogonal Analysis of Rock Slope

In order to analyze the force and deformative characteristics of pile foundation on rock slope and study the influence degree of pile foundation on multiple factor,an orthogonal experiment was conducted according to the orthogonal experimental principle;and the large current FEM program MSC.Marc was adopted to carry out the numerical simulation so as to analyze how the change of the factors influences deformation and the force.The results showed that the data getting from the orthogonal design and FEM method accorded with general engineering instance,and the method was reliable.The influence of different factors on horizontal displacement has its own order:internal friction angle> vertical load and uniform load> horizontal load and slope angle> cohesion and diameter;on maximum moment:internal friction angle> diameter and cohesion> slope angle and horizontal load> uniform load and vertical load.The strength of rock around pile had the greatest influence on displacement and the internal force of pile;the strength and integrality of rock should be protected as well as possible.Moreover,the pile foundation on rock slope had characteristics of passive pile and uniform load on top of slope had more influence on displacement of pile,so heaped load on top of slope should be avoided in construction process.