膨胀岩边坡蠕变数值模拟研究
发布时间：2018-10-12 18:24
【摘要】：膨胀岩因强度相对较低,具有较为明显蠕变特性。由于膨胀岩含有膨胀性矿物成分,具有吸水膨胀软化特性,吸水软化后其蠕变特性会更加明显。本文用FLAC3D软件分别以低含水率(7.415%)和高含水率(23.35%)的膨胀岩挖方边坡为例开展了蠕变数值模拟研究,并在含水率为7.415%的膨胀岩挖方边坡基础上进行了不同降雨入渗深度和不同表面饱和层厚度条件下膨胀岩边坡软化蠕变数值模拟研究,得到了下面的结果：考虑蠕变作用的膨胀岩边坡稳定性更符合工程实际。低含水率(7.415%)膨胀岩边坡在蠕变作用下呈整体蠕变运动趋势,处于相对稳定状态;高含水率(23.35%)膨胀岩边坡在蠕变作用下易形成从坡脚至坡顶贯通的大剪应变增量带而产生局部加速滑动。天然开挖及降雨入渗条件下膨胀岩边坡蠕变,均以剪切破坏为主,在坡顶有拉破坏的可能。膨胀岩边坡在降雨入渗时,会引起剪应力重分布,坡体内剪应力会增大,随入渗深度增加而更容易从坡面附近发生剪切破坏。在降雨入渗2m深度(表面0.5 m饱和)和降雨入渗7m深度(表面0.5 m饱和)两种工况时,边坡蠕变位移随着入渗深度增大而增大,稳定阶段蠕变速率随入渗深度增大而增大,但没有出现滑坡。在降雨入渗3m深度(表面1m饱和)时,会很快出现表层条带滑动,说明饱和层厚度对膨胀岩边坡稳定性影响大。
[Abstract]:The swelling rock has obvious creep characteristics because of its relatively low strength. The swelling rock contains expansive mineral components and has the characteristics of water absorption swelling and softening, and the creep property of the swelling rock will be more obvious after water absorption softening. In this paper, the creep numerical simulation of expansive rock excavation slope with low water content (7.415%) and high water content (23.35%) has been carried out using FLAC3D software. The numerical simulation of softening and creep of expansive rock slope with different rainfall infiltration depth and different surface saturation layer thickness was carried out on the basis of swelling rock excavation slope with 7.415% water cut. The following results are obtained: the stability of expansive rock slope considering creep is more in line with engineering practice. The swelling rock slope with low moisture content (7.415%) shows a whole creep movement trend under creep action and is in a relatively stable state. The swelling rock slope with high moisture content (23.35%) is easy to form a large shear strain increment zone from the foot of the slope to the top of the slope under the creep action resulting in local accelerated sliding. Under the condition of natural excavation and rainfall infiltration, the creep of expansive rock slope is mainly caused by shear failure, and there is a possibility of tensile failure at the top of the slope. When the expansive rock slope is infiltrated with rainfall, the shear stress will be redistributed, and the shear stress in the slope will increase, and the shear failure will occur more easily from near the slope with the increase of infiltration depth. When rainfall infiltration depth is 2m (surface 0.5 m saturation) and rainfall infiltration 7 m depth (surface 0.5 m saturation), the creep displacement of slope increases with infiltration depth, and creep rate increases with infiltration depth at stable stage. But there was no landslide. When rainfall infiltration depth is 3 m (surface 1 m saturation), the slip of surface zone will occur quickly, which indicates that the thickness of saturation layer has a great influence on the stability of expansive rock slope.
【学位授予单位】：广西大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TU452
本文编号：2267147
[Abstract]:The swelling rock has obvious creep characteristics because of its relatively low strength. The swelling rock contains expansive mineral components and has the characteristics of water absorption swelling and softening, and the creep property of the swelling rock will be more obvious after water absorption softening. In this paper, the creep numerical simulation of expansive rock excavation slope with low water content (7.415%) and high water content (23.35%) has been carried out using FLAC3D software. The numerical simulation of softening and creep of expansive rock slope with different rainfall infiltration depth and different surface saturation layer thickness was carried out on the basis of swelling rock excavation slope with 7.415% water cut. The following results are obtained: the stability of expansive rock slope considering creep is more in line with engineering practice. The swelling rock slope with low moisture content (7.415%) shows a whole creep movement trend under creep action and is in a relatively stable state. The swelling rock slope with high moisture content (23.35%) is easy to form a large shear strain increment zone from the foot of the slope to the top of the slope under the creep action resulting in local accelerated sliding. Under the condition of natural excavation and rainfall infiltration, the creep of expansive rock slope is mainly caused by shear failure, and there is a possibility of tensile failure at the top of the slope. When the expansive rock slope is infiltrated with rainfall, the shear stress will be redistributed, and the shear stress in the slope will increase, and the shear failure will occur more easily from near the slope with the increase of infiltration depth. When rainfall infiltration depth is 2m (surface 0.5 m saturation) and rainfall infiltration 7 m depth (surface 0.5 m saturation), the creep displacement of slope increases with infiltration depth, and creep rate increases with infiltration depth at stable stage. But there was no landslide. When rainfall infiltration depth is 3 m (surface 1 m saturation), the slip of surface zone will occur quickly, which indicates that the thickness of saturation layer has a great influence on the stability of expansive rock slope.
【学位授予单位】：广西大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TU452
【引证文献】
相关会议论文 前1条
1 黄玉灵;陈明祥;;岩石蠕变对边坡稳定性影响的数值分析[A];岩土力学数值方法的工程应用——第二届全国岩石力学数值计算与模型实验学术研讨会论文集[C];1990年
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