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1、【精品文档】如有侵权，请联系网站删除，仅供学习与交流黏土性边坡的应力及变形量分析.精品文档.黏土性边坡的应力及变形量分析200900406 刘亚辉摘要：本文就岩土工程中土质边坡中的黏性土边坡在重力及均布压力和集中力作用下的应力及由应力产生的变形量进行分析。建立水平半空间无限体模型运用弹性力学的空间问题的解法来求出所受应力，并用土力学中的地基沉降理论确定其中未知量求出其铅直位移，后进行角度转化推广至非水平问题既是其变形量，根据变形量可以判断边坡的稳定，继而进行稳定性分析.关键词：黏土性边坡 均布压力 集中力 应力 变形量 引言：边坡是指的是为保证路基稳定，在路基两侧做成的具有一定坡度的坡面。按地
2、层岩性分类：可分为土质边坡和岩质边坡。而我们所要研究的是土质边坡的一种常见边坡黏土性边坡。黏性土边坡常用于渠道、土坝、基坑，是常见的而且运用较广的一种边坡类型，尤其在岩土工程中。边坡受力方式主要为均布力和集中力，在两种受力情况下会导致不同的应力情况和变形情况。一、受到重力和均布荷载作用下的变形计算 把边坡建立成水平的半无限空间体模型进行分析设有半空间体，密度为，在水平边界上受均布压力q，如图1，以边界面为xy面，z轴铅直向下。这样，体力分量就是用位移法求解可得出所求在x，y，z方向的应力 （1）得出铅直位移显然，最大的位移发生在边界上，既z=0并由此求出铅直位移 （2）因为为半空间无限体在水平
3、边界上的位移为零，故铅直位移就是所求的变形量。但问题又出来了，既然我们建立的模型为半空间无限体，则（2）式中的h便为无限大，这样，所求式子便无意义。所以我们结合土力学的关于一些关于土的固结与压缩的知识进行分析。同样假设该边坡为水平边坡为半空间无限体，受重力和均布荷载。已知自重应力、附加应力和荷载的水平宽度（基础宽度）b，如图2图2具体方法为：（1） 将地基分层，每层厚度或（2） 计算附加应力分布（3） 计算自重应力分布（4） 我们研究的是黏性土故求出时的h值此时h即为公式（2）中所求h值。然后根据实验数据把具体数值代入即可得到我们要求的铅直位移。由此，我们可以求出在均布荷载情况下的此模型的应力
4、和弹性形变。二、在边界上受法向集中力作用下的变形计算同样建立一个半空间体模型，体力不计，在水平边界上只受发向集中F，如图（3）图3用弹性力学方法可求出其在z轴方向上的应力 （3）由土的z轴方向上的应力和侧压力系数K可以求出在边界上的水平分力，同时可以把和看做最大主应力和最小主应力。同样，在水平边界上的应力可忽略不计，设任意一点的沉降为（4）我们求的是边界上任意点处的沉陷所以（5）对于建立的半空间无限大模型而言其受力为F时在受力点时，由式（5）可知沉陷量应为无穷大，很显然实际上不可能是无限大！由于是模型，有很多假设，这些假设在现实中不可能成立，所以，不可能是无限大。由应力式（3）可知所在离集中力
5、远的地方应力非常小，在离集中力处应力相应的大。所以同样可以看出沉陷量与的关系。以上我们研究的是在水平方向上的边坡模型，而在现实中，没有边坡是水平，边坡都有一定的坡度，而在相应坡度上的压缩量，和这些压缩所能产生破坏，才是我们应该研究的！三、在半空间无限体模型为与水平方向有一定夹角设坡角为，则重力所产生的法向分力同时，再受均布荷载时q时，在边界上的法向位移为在忽略竖直方向的压缩量时（在实际中不应忽略，但由于水平所限，只能求得理想情况）既为黏土边坡的压缩量。再受集中力作用下由于同样是法向所以所以边界的沉降量应与水平时相同（忽略有重力造成的竖直方向的），为求出由外力产生的形变位移，根据压缩量和剪切破坏
6、，判断边坡的稳定性。四、边坡破坏的地质破坏由于我们研究的法向应力作用下的破坏，可以求出的法向应力在边坡上求出最大主应力和最小主应力，由于是黏性土，设为正常固结可以求出其剪切力如果小于其所能承受的最大剪应力，该边坡是稳定的；而当时，会产生剪切破坏。边坡还是稳定土体的一种挡土建筑物，其作用还能挡住墙后的填土并承担来自填土侧向的压力，就是所谓的承受土压力。在这种情况下，可以把来自填土的压力看成是外力的一种，只是方向相反，所以我们推出的公式依然适用，只需把土压力看成重力的一种，按重力地方法来进行计算即可，这里不再过多讨论。参考文献：1卢廷浩.高等土力学M.北京：机械工业出报社，20062蔡中林 黄临平
7、.弹性流变力学M北京：原子能出版社，20053李仲春.水利水电工程地质论文集M河南：黄河水利出版社，20044孙广忠.工程地质与地质工程M北京：地震出版社，19935徐芝纶.弹性力学简明教程.北京：高等教育出版社，2002 Clay of slope stress and deformation analysis200900406 Liu YahuiAbstract: This article on the geotechnical engineering soil slope of cohesive soil slopes under gravity and uniform pressure
8、 and concentration under the action of stress and the stress deformation analysis. Establishment of the horizontal half-space model by means of elastic mechanics solution to calculate the space stress, and soil mechanics in foundation settlement theory to determine which the unknown quantity and the
9、 vertical displacement, after conversion and extension to the non horizontal angle problem since the deformation, the deformation can be judged according to the slope stability, then the stability analysis.Key words: clay slope uniform stress concentration stress deformationAbstract: slope is refers
10、 to in order to ensure the stability of roadbed, roadbed made in both sides has a certain slope slope. According to the lithology classification: can be divided into soil slope and rock slope. We should study is a kind of common soil slope slope - clay slope. Cohesive soil slope is often used for ch
11、annels, earth dam, foundation pit, is common and is widely used as a type of slope, especially in geotechnical engineering. Slope stress mainly uniform load and concentrated force, in two under the condition of stress will result in different stress and deformation. One, by gravity and uniformly dis
12、tributed load deformation calculationThe slope of the level of semi infinite half space model analysisA semi-infinite space, density, in the horizontal boundary subjected to uniform pressure Q, as shown in Figure 1, with a boundary surface for XY, Z axis vertical downward. Thus, physical componentDi
13、splacement method for solving the request in X, y, z directions of stress ( 1)The vertical displacementObviously, the maximum displacement occurs in the boundary, both z = 0 and thus calculate the vertical displacement ( 2)As for the half-space in horizontal boundary displacement is zero, so the ver
14、tical displacement is the desired deformation.But the problem is coming out again, since our model for the half-space, then (2 ) type of H is infinite, so that, for there is no significanceSo we combine the soil mechanics about some of the soil consolidation and compression of the knowledge analysis
15、.It also assumes that the slope of horizontal slope for half-space, gravity and uniformly distributed load. Known gravity stress, additional stress and load level width ( width B Foundation ), such as in Figure 2 and Figure 2The specific method for:( 1) the foundation layer, the thickness of each la
16、yer or( 2) calculation of additional stress distribution( 3) calculated self-weight stress distribution( 4) we are therefore seeking out of cohesive soil valueAt this point the H is the formula (2 ) and H value in. Then according to the experimental data to specific numbers can be our requirements f
17、or vertical displacement.Thus, we can calculate the uniformly distributed load cases the model of stress and elastic deformation.Two, on the border of a normal force on the deformation calculationThe same set 1.5 space model, physical problems, in the horizontal boundary subject only to the concentr
18、ation of F, as shown in Figure 3 ( 3)With the method of elastic mechanics can be derived in the direction of Z axis of stress ( 3)The soil in the Z axis direction of the stress and lateral pressure coefficient K can be obtained in the boundary of the horizontal component, at the same time can turn a
19、nd as the maximum principal stress and principal stress.Similarly, in the horizontal boundary stress can be neglected, set an arbitrary point of settlement for ( 4)We seek is the boundary on any point of settlement so(5)For the establishment of the half space infinite model the stress of F in force,
20、 by type ( 5 ) the subsidence quantity should be infinite, obviously cant really be infinite! Because the model, there are many hypotheses, these assumptions in reality impossible, therefore, may not be infinite. The stress type (3 ) that is far from the local stress concentration is very small, fro
21、m the concentrated load stress corresponding to the large. It also can be seen in the settlement of the relationship with the.We study in the horizontal direction on the model of the slope, but in reality, there is a level of slope, slope has a certain slope, and in the corresponding gradient compre
22、ssion amount, and the compression can be destroyed, that we should study!In three, half-space model has a certain angle with the horizontal directionA slope angle, gravity generated by normal componentAt the same time, more uniform load Q, on the boundary of the displacement for theIn ignored vertic
23、al amount of compression ( in practice should not be ignored, but due to a limited level, can achieve ideal ) for both the amount of compression of clay slope.Be under the concentrated force is normal so due to the same boundary settlement should be at the same level ( ignore gravity caused by verti
24、cal ), for theCalculate the deformation displacement caused by the external force, according to the amount of compression and shear failure, judge the stability of the slope.Four, failure of slope geological damageBecause we study the normal stress under the action of damage, can find out the normal
25、 stress on the slope of the maximum principal stress and minimum principal stress, as is the cohesive soil, set to normal consolidation can calculate the shear stressIf less than the maximum shear stress, the slope is stable; and when, will generate shear failure.Slope stability of soil is a soil re
26、taining structure, its role can block wall after filling and bear from soil lateral pressure, is the so-called under soil pressure. In this case, can from the filling pressure as the external one, but in the reverse direction, so we introduced formula still apply, only the soil pressure as gravity a
27、, according to the gravity method to calculate can, here no longer talk too much.Reference: 1 Lu Tinghao. Advanced soil mechanics M. Beijing: Mechanical Industry Press, 20062 Cai Zhonglin Huang Linping. Elastic rheology mechanics M . Beijing: Atomic Energy Press, 2005Li Zhongchun 3. Water conservancy and hydropower engineering geology M . Henan: the Yellow River Water Conservancy Press, 2004Sun Guangzhong 4. Engineering geology and geological engineering M . Beijing: Earthquake Press, 19935 Xu Zhiguan. Elastic mechanics. Beijing: Higher Education Press, 2002