| 层厚比对水平砂泥岩互层岩体抗剪强度参数的影响 |
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| 引用本文： | 崔华龙,叶四桥.层厚比对水平砂泥岩互层岩体抗剪强度参数的影响[J].水文地质工程地质,2018,0(6):78-78. |
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| 作者姓名： | 崔华龙 叶四桥 |
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| 作者单位： | 重庆交通大学河海学院，重庆400074 |
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| 基金项目： | 国家自然科学基金项目资助（50678182；51108488） |
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| 摘 要： | 现有标准规定砂泥岩互层岩体的抗剪强度参数，当层厚在5 m以下时按泥岩取值，对不同工程场景、不同的层厚比例关系未做进一步区分。引入泥岩层厚与砂岩层厚之比，即层厚比，利用FLAC3D建立不同层厚比的水平砂泥岩互层岩体三轴数值试验模型，探索了层厚比对水平砂泥岩互层岩体的抗剪强度参数和变形特征的影响规律。结果表明:当岩层总厚度不变，层厚比以0.75为界，当层厚比小于0.75时，层厚比越小岩体黏聚力越大，反应砂岩对岩体黏聚力有增大效应，在此区间内水平砂泥岩互层岩体黏聚力可按1～4倍的泥岩黏聚力取值；同样，岩体内摩擦角仅按泥岩取值也不客观，但其随层厚比的变化规律不明显。当层厚比大于0.75时，水平砂泥岩互层岩体抗剪强度参数按泥岩取值是可行的。当层厚比不变，层厚对水平砂泥岩互层岩体的抗剪强度参数有明显影响，层厚比小于0.2时，互层岩体的黏聚力随层厚变化较大；层厚比大于0.2时，互层岩体的黏聚力随层厚的变化较小，可按泥岩取值。层厚比小于0.75时，互层岩体的内摩擦角随层厚变化较大；层厚比大于0.75时，岩体内摩擦角随层厚的变化较小，可按泥岩取值。水平砂泥岩互层岩体的变形特征也同岩体层厚比和层厚有关。层厚比较小时，岩体变形发生在砂岩层，破坏范围较大；随着层厚比的增大，其变形破坏发生在软岩部分，硬岩部分基本不出现变形或出现少量变形；若岩体层厚比不变，层厚减小，岩体的变形范围变大。
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| 关 键 词： | 岩体 抗剪强度参数 层厚比 砂泥岩互层岩体 |
| 收稿时间： | 2018-05-08 |
| 修稿时间： | 2018-06-19 |
Effect of different thickness ratio of horizontal interbedded mudstone and sandstone layers on shear strength parameters |
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| CUI Hualong,YE Siqiao.Effect of different thickness ratio of horizontal interbedded mudstone and sandstone layers on shear strength parameters[J].Hydrogeology and Engineering Geology,2018,0(6):78-78. |
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| Authors: | CUI Hualong YE Siqiao |
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| Institution: | School of Hehai, Chongqing Jiaotong University, Chongqing400074, China |
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| Abstract: | According to the existing codes, when the thickness of a layer is less than 5 m, the shear strength parameters of horizontal interbedded sandstone and mudstone are the same as those of mudstone. However, for different project scenes and thickness ratios, the shear strength parameters have not been further distinguished. The ratio of mudstone thickness to sandstone thickness is introduced in this paper and the tri-axial numerical test model with different thickness ratios is established by using FLAC3D. The effect of the shear strength parameters and deformation characteristics of the horizontal interbedded sandstone and mudstone rock mass is explored. The results show that when the layer thickness ratio is less than 0.75, the smaller the layer thickness ratio is, the greater the cohesion is. This reflects the increasing effect of sandstone on the cohesion of the rock mass. In this interval, the cohesion of the horizontal interbedded sandstone and mudstone rock mass can be valued at 1 to 4 times the mudstone cohesion. In the same way, the internal friction angle in the rock mass is not objective only according to the value of mudstone, but the law of its variation with layer thickness ratio is not obvious. When the layer thickness ratio is greater than 0.75, it is feasible that the shear strength parameters of the horizontal interbedded sandstone and mudstone rock mass are selected based on the mudstone value. When the layer thickness ratio is constant, the layer thickness has obvious influence on the shear strength parameters of the horizontal interbedded sandstone and mudstone rock mass. When the layer thickness ratio is less than 0.2, the cohesive force of the interbeded rock mass varies greatly with the layer thickness, which also indicates that the value of the mudstone alone is not objective. When the layer thickness ratio is greater than 0.2, the shear strength parameter varies little with the layer thickness and can be selected based on the mudstone value. When the layer thickness ratio is less than 0.75, the internal friction angle of the interbeded rock mass varies greatly with the layer thickness, which also indicates that the value of the mudstone alone is not objective. When the ratio of layer thickness to thickness is greater than 0.75, the friction angle within the rock mass changes little with the layer thickness, which can be chosen according to the mudstone value. |
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