| 隐伏正断层错动引发上覆土体破裂过程的三维数值模拟 |
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| 引用本文： | 齐剑峰,赵心怡,王成真,郝文拯.隐伏正断层错动引发上覆土体破裂过程的三维数值模拟[J].地震学报,2019,41(1):124-137. |
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| 作者姓名： | 齐剑峰 赵心怡 王成真 郝文拯 |
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| 作者单位： | 中国石家庄 050031 河北地质大学勘查技术与工程学院;中国石家庄 050031 河北地质大学勘查技术与工程学院;中国石家庄 050031 河北地质大学勘查技术与工程学院;中国石家庄 050031 河北地质大学勘查技术与工程学院 |
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| 基金项目： | 河北省自然科学基金（D2017403020）和国家自然科学基金创新群体项目（51421005）联合资助 |
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| 摘 要： | 通过建立三维数值模型，对隐伏正断层在均匀错动和倾斜错动方式下土体的破裂过程进行研究。利用应力罗德参数和等效塑性应变分别对断层错动过程中上覆土体的应力状态和破坏形式进行分析，并提出土体破裂的判别方法。通过对数值模拟结果的分析得到以下结论:① 在断层错动过程中，下盘一侧受断层错动影响的上覆土体的应力状态经压剪→纯剪→拉剪逐渐变化，而上盘一侧上覆土体的应力状态变化较为复杂，经压剪→纯剪→拉剪→纯剪→压剪重复变化；② 在断层均匀错动过程中，断层下盘一侧土体的破裂率先出现在地表拉剪区内，随错动量的增大，破裂带向两侧、向深部扩展；同时，下盘一侧土体的底部产生破坏，并斜向上扩展，逐渐与顶部破裂相连；③ 在断层倾斜错动过程中，地表破裂出现的位置和上覆土体的厚度有关。对于厚度较大的土体，正断层倾斜错动能够在地表形成与断层走向有一定夹角、且与断层长度相比长度很短的地表破裂或地裂缝，而数值模拟可对正断层错动导致的地表破裂的模式加以补充，为研究地裂缝的形成机理和分布形式提供依据。
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| 关 键 词： | 破裂 上覆土体 应力状态 塑性变形 正断层 数值模拟 |
| 收稿时间： | 2018-02-27 |
Three-dimensional numerical simulation of rupture process of overlying soil caused by buried normal fault movement |
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| Institution: | 1.Laboratory of Water Resources Sustained Utilization and Development in Hebei Province，Shijiazhuang 050031，China2.Hebei GEO University，Institute of Exploration Technology and Engineering，Shijiazhuang 050031，China |
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| Abstract: | The rupture process of overlying soil caused by uniform movement and inclined movement of buried normal fault was studied by setting a three-dimensional numerical model. The stress state and failure style of overlying soil are respectively analyzed by using stress Lode parameter and equivalent plastic strain during fault movement, and a discrimination method of soil rupture is recommended. The conclusions are drawn as follows through analyzing the results of numerical simulation: ① As affected by fault movement, the stress state of overlying soil on the footwall side of the fault varies via compression-shear → pure-shear → tension-shear during fault movement, and the soil stress state on the upper wall side of the fault is fairly complex, which repetitively varies via compression-shear → pure-shear → tension-shear → pure-shear → compression-shear. ② For the uniform movement of the fault, the surface soil ruptures firstly occur at the tension-shear area on the footwall side of the fault, and with fault movement increased, the ruptures develop towards both sides as well as downward. Meantime, the bottom soil failures occur on the footwall side of the fault and develop obliquely upward, and finally connected with the rupture of surface soil. ③ For the inclined movement of the fault, the positions of soil rupture are relative with the thickness of overlying soil. When the overlying soil is thick, the surface soil ruptures or ground fissures occur due to the fault movement, which have an angle with the fault strike, and are much shorter than the fault. The numerical simulations can reveal the surface soil rupture patterns and will provide the basis for the studies on the origin and distributed patterns of ground fissures. |
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