【作者】 刘杰；

【导师】 杨仕教；

【作者基本信息】 南华大学 ， 土木工程， 2018， 硕士

【摘要】 目前工程上针对地质条件复杂、支护空间有特殊要求的高边坡采用传统单一的支护结构难以满足实际需要,双排桩与悬臂式挡墙组合结构能较好解决这种难题,目前这种复合结构一般将上下两部分分开单独设计,未考虑上下结构之间的受力协调作用与整体支护稳定性,故导致设计结果偏离实际。本文以双排桩与悬臂式挡墙组合结构为研究对象,借助数值模拟方法研究单独设计与整体联合支护设计间的差异,并分析土体和桩身设计参数变化下组合结构内力变化规律。主要研究工作如下:(1)模型简化。选取某一实际工程案例,选取土体与支挡结构计算参数,按工程上常用单独设计与整体联合设计方法对边坡与组合支挡结构进行模型简化。(2)数值模拟。利用数值模拟手段建立双排桩与悬臂式挡墙组合结构有限元分析模型,根据组合结构内力结果选取内力变化特征点。(3)单独设计方法与整体联合设计方法对比。采用单独设计方法与整体联合设计法建立三种设计简化模型,将三种简化模型进行数值模拟得到挡墙与双排桩内力变化,进行对比得到组合结构在实际工程设计中存在的差异,分析边坡支护效果。(4)土层参数变化下受力特性分析。在对组合结构数值模拟的基础上,选取边坡支护土体材料的主要影响因素,利用蒙特卡罗随机抽样法产生土层参数随机样本组,研究在岩土体材料参数变化下双排桩与悬臂式挡墙组合结构内力特征点的受力特性,得到土层参数变化对该组合结构内力变化规律影响。(5)桩身设计参数变化下受力特性分析。研究不同参数变化条件下组合结构受力特性变化规律,分别考虑桩排距、连系梁截面尺寸与前后排桩嵌岩桩长比对结构内力、桩周与桩间土体应力变化的影响,对设计参数进行一定优化,得出较合理的桩身设计参数。通过本文研究,获得主要结论如下:(1)工程上组合结构单独设计方法相对于整体联合支护设计方法偏于保守,且容易造成材料浪费。(2)利用蒙特卡洛随机抽样得到样本组进行有限元计算表明:组合结构内力特征点位置变化极小。(3)综合考虑各因素影响,桩排距取4m、连系梁截面尺寸取与桩身截面尺寸相同较优;前后排桩嵌岩深度取4m为较优。更多还原

【Abstract】 At present,the traditional single support structure can not meet the actual needs for high slopes with complex geological conditions and special requirements for supporting space.The combination of double-row piles and cantilevered retaining walls can better solve this problem.The problem is that this composite structure generally separates the upper and lower parts separately and does not consider the force coordination and the overall support stability between the upper and lower structures,which leads to a deviation from the actual design results.This paper takes the composite structure of double-row piles and cantilevered retaining walls as the research object,and studies the differences between the separate design of the composite structure and the combined support design by means of numerical simulation methods,and analyzes the changes in the internal forces of the composite structure under the changes of the design parameters of the rock and soil and the pile body.law.The main research work is as follows:(1)The model is simplified.Select a practical project case,select the calculation parameters of the soil and retaining structure,and simplify the model of the slope and the combined retaining structure according to the commonly used separate design and overall joint design method in the project.(2)Numerical Simulation.The finite element analysis model of the double-row pile and cantilevered retaining wall combined structure was established by numerical simulation.According to the results of the internal force of the composite structure,the internal force variation feature points were selected.(3)The individual design method is compared with the overall joint design method.Three design simplification models were established using the separate design method and the overall joint design method.Three kinds of simplified models were used to perform numerical simulations to obtain internal force changes of the retaining wall and double row piles.The differences in the actual structure design of the combined structure were compared and analyzed.Slope support effect.(4)Analysis of the characteristics of soil under the change of soil parameters.Based on the numerical simulation of the composite structure,the main influencing factors of the soil material supported by the slope are selected,and the Monte Carlo random sampling method is used to generate a random sample set of soil parameters to study the double-row piles under the change of rock material parameters.With the force characteristics of the internal force characteristic points of the combined structure of the cantilevered retaining wall,the effect of the variation of soil parameters on the internal force variation law of the composite structure is obtained.(5)Analysis of Force Characteristics under Change of Design Parameters of Piles.Studying the variation of force characteristics of the composite structure under different parameters,considering the effects of pile spacing,connecting beam size,and rock-socketed pile length ratios of the front and rear piles,the internal forces of the structure,the stress of the soil around the pile and between the piles,The design parameters are optimized to obtain more reasonable pile design parameters.Through this study,the main conclusions are as follows:(1)The separate design method of the combined structure in the engineering is conservative in comparison with the overall combined support design method,and it is easy to cause material waste.(2)Using Monte Carlo random sampling to obtain the sample group for finite element calculation shows that the position of the feature points of the internal structure of the composite structure has very little change.(3)Considering the influence of various factors,the distance between piles is 4m.The section size of the tie beam is the same as the section size of the pile body.The depth of the rock plugs in the front and rear row is 4m.更多还原