边坡稳定性分析

边坡稳定性分析1内容摘要目前，边坡失稳的防治仍然是一项很艰巨的任务，对边坡的稳定性分析及处治技术进行深入研究具有重要的意义。论文首先简要阐述了边坡工程稳定性分析及处治技术研究的意义，介绍了边坡工程稳定性分析的一些常用方法，并结合笔者的实践经验，提出了边坡工程处治对策。边坡稳定分析是岩土工程中的重要研究课题。边坡稳定性分析的观点变化是随着人类理论方面的突破和实践经验的积累而变化的。总的来说,边坡稳定性分析是一个逐步由定性分析向定量、半定量分析发展的过程,并且可视化程度越来越高。文章从定性分析、定量分析、不确定分析等角度介绍了几种主要的边坡稳定性分析方法关键词：边坡；边坡稳定性；边坡失稳；稳定性分析；处治对策边坡稳定性分析2目录内容摘要···························································································11绪论·························································································41.1边坡稳定性概念·········································································41.1.1边坡体自身材料的物理力学性质·················································41.1.2边坡的形状和尺寸···································································51.1.3边坡的工作条件······································································51.1.4边坡的加固措施······································································51.2边坡的稳定性表示方法································································51.3边坡破坏··················································································62边坡的分类··················································································63边坡稳定性的影响因素·································································73.1潜在影响因素············································································73.1.1地形因素···········································································73.1.2地质材料因素·····································································73.1.3地质构造因素·····································································83.2诱发影响因素············································································83.2.1环境因素···········································································83.2.2人为因素···········································································94边坡稳定性的分析方法·······························································104.1定性分析方法··········································································104.1.1工程地质类比法································································104.1.2地质分析法(历史成因分析法)··············································104.1.3图解法·············································································104.1.4边坡的分析数据库和专家系统··············································114.2定量分析方法··········································································114.2.1极限平衡法······································································11边坡稳定性分析34.2.2数值分析方法···································································114.3不确定性分析方法····································································134.3.1系统可靠性分析法·····························································134.3.2灰色系统法······································································134.3.3模糊分级评判法································································134.3.4神经网络法······································································137结语·······················································································15参考文献·························································································16边坡稳定性分析41绪论1.1边坡稳定性概念边坡一般是指具有倾斜坡面的土体或岩体，由于坡表面倾斜，在坡体本身重力及其他外力作用下，整个坡体有从高处向低处滑动的趋势，同时，由于坡体土（岩）自身具有一定的强度和人为的工程措施，它会产生阻止坡体下滑的抵抗力。一般来说，如果边坡土（岩）体内部某一个面上的滑动力超过了土（岩）体抵抗滑动的能力，边坡将产生滑动，即失去稳定；如果滑动力小于抵抗力，则认为边坡是稳定的。在工程设计中，判断边坡稳定性的大小习惯上采用边坡稳定安全系数来衡量。1955年，毕肖普（A.W.Bishop）明确了土坡稳定安全系数的定义：fFs式中：f——沿整个滑裂面上的平均抗剪强度；——沿整个滑裂面上的平均剪应力；Fs——边坡稳定安全系数。按照上述边坡稳定性概念，显然，Fs1，土坡稳定；Fs1,土坡失稳,Fs＝1，土坡处于临界状态。毕肖普的土坡稳定安全系数物理意义明确，概念清楚，表达简洁，应用范围广泛，在边坡工程处治中也广泛应用。其问题的关键是如何寻求滑裂面，如何寻求滑裂面上的平均抗剪强度f和平均剪应力。边坡的稳定是一个比较复杂的问题，影响边坡稳定性的因素较多，简单归纳起来有以下几方面：1.1.1边坡体自身材料的物理力学性质边坡体材料一般为土体、岩体、岩土及其他材料混合堆积或混合填筑体（如工业废渣、废料等），其本身的物理力学性质对边坡的稳定性影响很大，如抗剪强度（内摩擦角，凝聚力c）、容重（包括天然容重和饱和容重等）。边坡稳定性分析51.1.2边坡的形状和尺寸这里指边坡的断面形状、边坡坡度、边坡总高度等。一般来说，边坡越陡，边坡越容易失稳，坡度越缓，边坡越稳定；高度越大，边坡越容易失稳，高度越小，边坡越稳定。1.1.3边坡的工作条件边坡的工件条件主要是指边坡的外部荷载，包括边坡和边坡顶上的荷载、边坡后传递的荷载，如公路路堤边坡顶上的汽车荷载、人行荷载等，储灰场后方堆灰传递的荷载，水坝后方水压力等。边坡体后方的水流及边坡体中水位变化情况是影响边坡稳定的一个重要因素，它除自身对边坡产生作用外，还影响边坡体材料的物理力学指标。1.1.4边坡的加固措施边坡的加固是采取人工措施将边坡的滑动传送或转移到另一部分稳定体中，使整个边坡达到一种新的稳定平衡状态，加固措施的种类不同，对边坡稳定的影响和作用也不相同，但都应保证边坡的稳定。研究边坡稳定性的目的，在于预测边坡失稳的破坏时间、规模，以及危害程度，事先采取防治措施，减轻地质灾害，使人工边坡的设计达到安全、经济的目的。1.2边坡的稳定性表示方法边坡的稳定性通常以滑动面上的抗滑力与滑动力的比值，即抗滑稳定性系数来表示。这一比值越大，边坡越稳定；反之，边坡越不稳定。评价边坡稳定性的常用方法有下列4类(1)、定性分析法。通过对边坡的尺寸和坡形、边坡的地质结构、所处的地质环境、形成的地质历史、变形破坏形迹，以及影响其稳定性的各种因素的研究，判断边坡演变阶段和稳定状况。(2)、极限平衡分析法。把可能滑动的岩、土体假定为刚体，通过分析可能滑动面，并把滑动面上的应力简化为均匀分布，进而计算出边坡的稳定性系数。(3)、数值分析法。利用有限单元分析法，先计算出边坡位移场和应力场，然后利用岩、土体强度准则，计算出各单元与可能滑动面的稳定性系数。(4)、工程地质类比法。将所研究边坡或拟设计的人工边坡与已经研究过的或已有经验的边坡进行类比，以评价其稳定性，并提出合理的边坡稳定性分析6坡高和坡角。1.3边坡破坏边坡破坏的类型很多，常见的是崩塌和滑坡。陡坡前缘部分岩、土体突然与母体分离，翻滚跳动崩坠崖底或塌落而下的过程和现象，称为崩塌。边坡部分岩、土体沿着先前存在的地质界面，或新形成的剪切破坏面向下滑动的过程和现象，称为滑坡。在边坡破坏中，滑破是最常见，危害最严重的一类。所有的边坡失稳，均涉及到边坡岩、土体在剪切应力作用下的破坏。因此，影响剪切应力和岩、土体抗剪强度的因素，都影响边坡的稳定性。例如，构成边坡岩、土体的工程地质性质及其变化；边坡中断层、层面、不整合面等不连续面的产状与坡面倾向、倾角之间的关系；边坡尺寸和形态的改变；坡脚遭受水的侵蚀或人工开挖；边坡上天然或人工加载；边坡岩、土体中地下水位的升降，以及地震和爆破引起的瞬时振动等，均会在一定程度上改变边坡的稳定性。2边坡的分类在实际工程中，为满足不同工程用途的需要，边坡设计形态多种多样，边坡的分类通常有以下几种：(1)按照边坡的成因可分为天然边坡和人工边坡，天然边坡是自然形成的山坡和江河湖海的