【作者】 刘涛；

【导师】 刘畅； 刘永超；

【作者基本信息】 天津大学 ， 建筑与土木工程， 2018， 硕士

【摘要】 目前,倾斜桩在很多工程中都有所应用,例如公路桥梁、港口码头、输电线塔架及海上钻井平台等结构的基础中,而在我国深基坑支护工程中,排桩支护结构一直广泛采用直桩支护形式,很少使用倾斜桩。通过倾斜桩在现有工程中的应用,发现倾斜桩能够充分发挥其轴向抗压能力,减小风荷载、地震荷载、流水及波浪荷载等水平荷载引起的桩身剪力和弯矩。本文基于这一背景,将倾斜桩拓展使用至基坑支护工程,通过开展现场试验和有限元数值模拟分析,着重研究倾斜支护桩在基坑中的作用机理,并在库伦理论公式基础上推导出在一定倾角范围内单排倾斜桩的内力计算方法。本文首先对倾斜支护桩现场足尺试验做了简单的介绍和说明,并将试验结果进行了对比分析,发现倾斜支护桩倾斜角度越大,桩顶水平位移越小,相同角度的倾斜支护桩,斜直交替支护桩桩顶水平位移小于单斜桩。其次为了深入研究倾斜支护桩在基坑支护中的作用机理,采用针对岩土工程的变形和稳定问题的三维有限元分析软件PLAXIS 3D进行三维建模分析。通过与倾斜支护桩现场工程实例的试验结果对比,验证本文有限元模拟所依循的思路和方法的可行性及参数选取的合理性。对比斜桩倾斜角度在0°~20°范围内不同倾斜角度和不同布桩方式下桩顶水平位移,桩身侧移,桩身弯矩,土体位移和桩身土压力的变化规律,并应用强度折减法分析了支护桩倾斜角度和布桩方式对基坑整体稳定性的影响。最后,借助库伦理论公式和已有的传统竖直桩内力分析理论,推导出在一定倾角范围内单排倾斜桩内力的简化计算方法。更多还原

【Abstract】 At present,the inclined pile has been applied in many engineering projects.Such as the foundation of the structure in roads and bridges,port and pier,power line towers and offshore drilling platforms.However,inclined piles are rarely used in foundation pit supporting works.Most Chinese foundation pit supporting projects,straight pile supporting form has been widely used in row piles supporting structure.By analyzing the application of inclined piles in existing projects,we found that inclined piles can fully exert their axial compressive capacity and reduce the pile shear force and bending moment caused by horizontal loads such as wind load,seismic load,flowing water and wave load.Based on this background,we will apply the inclined pile to the actual excavation supporting engineering.With field test and finite element numerical simulation analysis,this paper emphatically studies the mechanism of slope supporting piles in foundation pit.Based on the formula of coulomb theory and existing traditional vertical pile internal force analysis theory,we deducted the calculation method of internal force of single row inclined pile in a particular inclination angle.In this paper,the application of inclined support pile in foundation pit is briefly introduced and explained,and the test results are compared and analyzed.And it is found that the greater the inclination angle of inclined support pile is,the smaller the horizontal displacement of pile top is,and the horizontal displacement of inclined support pile and alternate support pile with the same angle is smaller than that of the single inclined pile.In addition,in order to study the mechanism of inclined support pile in foundation pit support,three-dimensional modeling analysis is carried out by using the threedimensional finite element analysis software PLAXIS 3D,which designed fors the deformation and stability of geotechnical engineering.Through the test results of field engineering examples of inclined support pile,the feasibility and parameter selection of the ideas and methods of finite element simulation are verified.The main purpose of this paper is to analyse the rule of horizontal displacement of pile top,lateral displacement of pile body,the bending moment of pile body,displacement of soil body and earth pressure of pile under different inclination angles and different distribution methods,while the inclined angle lies between 0°~20°.What’s more,the effect of supporting pile inclination angle and pile distribution method on the overall stability of foundation pit is analyzed by strength reduction method.Finally,with the help of Coulomb theory formula and the existing theory of vertical force analysis of vertical piles,this paper will deduce the calculation method of internal forces of single-row inclined piles within a certain inclination angle.更多还原