【作者】 何国峰；

【导师】 林大泽； 宋建波；

【作者基本信息】 贵州大学 ， 岩土工程， 2008， 硕士

【摘要】 嵌岩桩是广大山区岩基上大型构(建)筑物重要的基础型式,目前虽已开展了大量的研究,但嵌岩群桩承载机理及设计理论目前仍是岩土工程、基础工程领域研究的空白。本论文在系统阐述层状岩体力学特性、嵌岩单桩承载机理的基础上,以三维有限元数值模拟手段,深入研究了嵌岩群桩的承载性状及优化设计理论,取得如下成果:(1)通过对层状岩体现有研究成果的总结和归纳,从强度和变形的角度,系统研究了层状岩体的力学性状;并将层状岩体分为水平和倾斜两种情况,分析了基础直接作用于岩体上时的受力特征。(2)以嵌岩单桩承载性状为研究重点,分析了全阻嵌岩桩的桩侧摩阻力与桩端阻力的承载机理、影响因素和计算方法。并以此为基础,理论分析了嵌岩群桩的承载机理,总结了现有规范中进行嵌岩单桩、嵌岩群桩的设计方法及其存在的不足。(3)在建立嵌岩群桩的理想计算模型的基础上,以三维有限元数值模拟为手段,结合嵌岩群桩的P-S曲线和各桩应力状态,系统研究了嵌岩群状的受荷过程,及桩长、嵌岩深度、桩身强度、基岩强度等对其承载性能的影响。(4)基于(3)中所建的嵌岩群桩计算模型,以三维有限元软件数值模拟为手段,结合嵌岩群桩的P-S曲线和各桩应力状态,系统研究了嵌岩群桩在改变桩长、改变嵌岩深度等情况下承载性状的变化,并系统总结了嵌岩群桩优化设计的原理与方法。本论文首次对贵州地区层状岩体中嵌岩群桩的承载性状与其优化设计理论开展了较为全面、系统的研究。这对提高嵌岩群桩承载机理的认识、指导嵌岩群桩的优化设计均有重要的理论意义、现实意义和较广阔的应用前景。更多还原

【Abstract】 Rock-socketed piles are the important foundation type for large building in mountain area. Although a lot of research was developed in the field of geotechnical engineering and foundation engineering, It’s blank to the bearing mechanism and optimization design of rock-socketed pile group. This paper made a systematic exposition of mechanical properties for layered rock mass and bearing mechanism of rock-socketed pile. On the basis of this, the load transferring capacity and the optimization design for rock-socketed pile group is studied thorough, by 3D finite element numerical simulation. The obtained achievements are listed as follow:1. According to the concludes and summarizes of the existing research results to layered rock mass, mechanical properties for layered rock mass is researched systematically from the view of strength and deformation; the stress characteristics for foundation effect directly on the upper of rock is analyzed on leveled and declined layered intrusion situation.2. Focus on the bearing behavior of rock-socketed pile, bearing mechanism, influencing factors and calculation method for side resistance and end resistance in whole resistance rock-socketed pile is analyzed. On the basis of this, this paper discusses the bearing mechanism of rock-socketed pile group, and summarizes the deficiency of the design method for rock-socketed pile in existing standard.3. By using three-dimensional finite element procedure, the calculation model of rock-socketed pile group was established. Through P-S curve and stress state for rock-socketed pile group, the bearing load process of rock-socketed pile group is researched. The paper discusses effection factors of bearing behavior such as pile length, rock-socketed length, pile strength, bedrock strength.4. Based on the established calculation model and 3D finite element numerical simulation, the variation of bearing behavior for rock-socketed pile group is researched on changing the pile length and rock-socketed length. And principle of optimum design for rock-socketed pile group is summarized systematically.This article firstly roundly and systematically theoretical studies the load transferring capacity and optimization design of rock-socketed pile group in layered rock mass of Guizhou Karst region. The research has significant theoretical meaning, practical meaning for further investigating working mechanism of rock-socketed pile group. Especially the optimization model provides a wide application prospect for the actual engineering.更多还原