挡土墙地震土压力的计算与分析

发布时间：2018-02-26 07:19

本文关键词： 挡土墙地震土压力斜向条分法黏性土拟动力法变位模式　出处：《海南大学》2015年硕士论文　论文类型：学位论文

【摘要】：挡土墙作为建筑、水利、交通等工程中一种常见的支挡结构,可以有效地防止墙后岩土体失稳破坏。地震作用对挡土墙土压力的影响显著,挡土墙的抗震设计已经成为岩土工程的重点课题之一,研究挡土墙地震土压力的计算方法具有重要的理论和实际意义。传统的Mononobe-Okabei(简称M-○)理论以库仑理论为基础,采用拟静力法将地震荷载简化为惯性力系作用于滑动楔体上,其计算过程简便,力学概念明确,成为支挡结构抗震设计的理论基础。然而,大量工程实践和研究表明：传统地震土压力理论的诸多假设使其适用范围具有一定的局限性,其计算结果也不能够完全反映挡土墙的实际受力状态,且理论本身也存在诸多争议。本文在总结前人研究成果的基础上,对挡土墙地震土压力计算理论进行了以下几个方面的研究工作： (1)采用散粒体极限平衡理论研究了作用在M-O理论假设的平面滑裂面上的土体反力分布及其合力作用点位置,并结合力矩平衡方法推导出地震土压力合力作用点高度的解析解,弥补了M-O理论不能求解地震土压力合力作用点位置及滑裂面反力的不足。 (2)基于M-O理论的假设,考虑填土粘聚力、墙土间粘着力、填土表面均布超荷载和黏性填土出现张拉裂缝等情况,利用极限平衡状态下滑动土楔体的静力平衡方程得到了广义地震土压力统一解。 (3)针对整体极限平衡分析法不能得到土压力的分布及其作用点位置的不足,考虑到地震作用下挡土墙偏转对土压力的影响,采用斜向条分法推导了复杂条件下黏性土挡土墙土压力强度分布、土压力合力及其作用点位置的计算式。 (4)采用拟动力学方法,考虑了地震加速度的放大效应以及地震作用的时间和相位变化,得到了黏性土地震土压力及其分布的半解析解,并研究了基于拟动力法的挡土墙抗倾覆和抗滑稳定性。 (5)针对挡土墙的不同变位模式,提出了相对应的地震土压力计算模型,并结合水平层分析法推导了地震土压力强度分布、土压力合力及其作用点位置的计算式,分析了挡土墙变位模式与折减系数对地震土压力的影响。本文有效完善了地震土压力计算理论,对支挡结构抗震设计有一定的参考价值。
[Abstract]:As the retaining wall construction, water conservancy, a common retaining structure in traffic engineering, can effectively prevent the wall rock failure. The earthquake had significant effects on the soil pressure of retaining walls, the seismic design of retaining wall has become one of the key topics in geotechnical engineering, has important theoretical and practical significance the calculation method of seismic earth pressure on retaining wall is studied.
The traditional Mononobe-Okabei (M- 2003) theory based on the Coulomb theory, using the pseudo static method of seismic load is simplified as the inertial forces acting on the sliding wedge, the calculation process is simple, clear mechanics concept, has become the theoretical basis of seismic design of retaining structures. However, a large number of engineering practice and research show that many assumptions the traditional seismic earth pressure theory and the range of application has some limitations, the results can not fully reflect the actual stress state of retaining wall, and the theory itself there are a lot of controversy. Based on the summary of previous research results, the seismic earth pressure on retaining wall calculation theory research works are as follows the:
(1) using granular limit equilibrium theory to study the effect in the plane M-O's theory on sliding surface soil anti force distribution and action point of resultant force, combined with the method of equilibrium of moments derived from seismic earth pressure application point of the resultant solution for M-O theory can not calculate the earth pressure resultant earthquake the sliding surface position and lack of reaction force.
(2) based on the hypothesis of M-O theory, considering the cohesive force of cohesive soil, the cohesive force between walls and soils, the distribution of overburden on the surface of the fill and the occurrence of tensile cracks in the clay filled soil, the unified solution of the generalized seismic earth pressure is obtained by using the static equilibrium equation of the sliding equilibrium of the earth moving wedge under the limit equilibrium condition.
(3) according to the limit equilibrium analysis method can not be lack of the earth pressure distribution and its position, considering the influence of the soil pressure of retaining wall deflection under the action of earthquake, the diagonal slice method is derived under complex conditions of cohesive soil retaining wall pressure distribution intensity, the calculation of earth pressure force and its position the type.
(4) by using pseudo dynamic method, considering the amplification effect of seismic acceleration and the time and phase changes of seismic action, we get the semi analytical solution of the earth pressure and its distribution of cohesive soil, and study the stability of retaining wall against overturning and skid resistance based on pseudo dynamic method.
(5) for retaining different displacement modes, put forward the corresponding seismic earth pressure calculation model, combined with the level analysis method to deduce the seismic earth pressure distribution, the calculation of earth pressure force and its point of application, analysis of retaining wall displacement modes and the reduction of the influence coefficient of seismic earth pressure.
This paper effectively improves the theory of seismic soil pressure calculation, and has a certain reference value for the seismic design of retaining structure.

【学位授予单位】：海南大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TU476.4;TU435

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