Experiment and Analysis of Surface Soil Rupture Pattern
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摘要: 近年来地震频发,研究断层区土体破裂形态是了解和认识地震断层破坏机制的关键。为研究不同断层类型对地表形态的影响,通过模型试验得到拉伸型断层、挤压型断层以及剪切型走滑断层的地表土层形态,同时对走滑断层进行了数值模拟计算,并与试验结果进行了对比。由试验结果可知,在拉伸型断层中,地表纵向拉伸变形随土层厚度的增大而减小。挤压型断层中,随着土层厚度的增大,地表纵向压缩变形减小,且减小趋势逐渐变缓,地表隆起区宽度和隆起高度随之增加。在走滑断层中,地表位错量随着土层厚度的增大而减小,且随着土层厚度的增大,地表变形影响区范围呈先增加后减小的趋势。数值模拟计算结果与走滑断层试验结果基本一致。Abstract: With the increasing frequency of earthquakes in recent years, studying soil rupture patterns in fault zones has become essential for understanding the damage mechanisms of earthquake faults. This research investigates the impact of different fault types on surface morphology through model tests and numerical simulations. Surface soil deformation patterns were examined for tensile faults, compressional faults, and strike-slip faults, and numerical simulations were conducted for strike-slip faults to compare with experimental results. The results from the tests reveal that for tensile faults, longitudinal tensile deformation of the ground surface decreases as soil layer thickness increases. In compressional faults, the longitudinal compressive deformation of the surface also decreases with increasing soil thickness, but at a slower rate. Additionally, the width and height of the surface uplift area increase with greater soil thickness. For strike-slip faults, surface dislocation decreases as soil thickness increases. Interestingly, the area affected by surface deformation initially expands and then decreases with increasing soil thickness. The numerical simulations of strike-slip faults align closely with the experimental findings, supporting the accuracy of the model tests.
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Key words:
- Tensile fault /
- Extrusion fault /
- Strike slip fault /
- Model test /
- Numerical simulation
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表 1 材料参数
Table 1. Material parameters
密度ρ/(g·cm−3) 黏聚力c/kPa 内摩擦角Φ/(°) 平均粒径
d50/mm有效粒径
d10/mm土粒
比重Gs最大孔
隙比emax最小孔
隙比emin弹性模量
E/kPa泊松比μ 1.52 7 30 0.253 0.008 2.67 0.919 0.411 20000 0.25 表 2 试验工况
Table 2. Test conditions
断层类型 断层预留宽度/cm 断层错动方向 断层错动距离/cm 土层厚度/cm 拉伸型断层 0 左盘向左 6 5、10、15、20 挤压型断层 6 左盘向右 6 5、10、15、20 走滑断层 0 右旋 3 5、10、15、20、25 -
刘学增,滨田政则,2004. 活断层破坏在土体中传播的试验研究. 岩土工程学报,26(3):425−427. doi: 10.3321/j.issn:1000-4548.2004.03.027Liu X. Z., Bin T. Z. Z., 2004. Experiments on rupture propagation of active faults in soil. Chinese Journal of Geotechnical Engineering, 26(3): 425−427. (in Chinese) doi: 10.3321/j.issn:1000-4548.2004.03.027 沈超,2020. 强震逆断层地表破裂的离心模型试验研究. 哈尔滨:中国地震局工程力学研究所.Shen C., 2020. Centrifuge tests on ground surface rupture induced by strong earthquake. Harbin:Institute of Engineering Mechanics,China Earthquake Administration. (in Chinese) 沈超,薄景山,李琪等,2022. 常重力模型实验在模拟断层错动中的应用. 地震工程与工程振动,42(1):122−131.Shen C., Bo J. S., Li Q., et al., 2022. Application of 1g-model experiment in simulating fault movement. Earthquake Engineering and Engineering Dynamics, 42(1): 122−131. (in Chinese) 石吉森,2017. 对断层错动引发上覆土层和隧道破坏的试验与数值研究. 杭州:浙江大学.Shi J. S., 2017. Model tests and numerical study on the destructions of overlaying soil and tunnels by faulting. Hangzhou:Zhejiang University. (in Chinese) 王强,2021. 强震地表破裂变形试验与数值模拟. 廊坊:防灾科技学院.Wang Q., 2021. Experiment and numerical simulation of surface rupture deformation under strong earthquake. Langfang:Institute of Disaster Prevention. (in Chinese) 徐龙军,彭龙强,谢礼立,2023. 地震断层形态研究综述. 世界地震工程,39(1):28−37.Xu L. J., Peng L. Q., Xie L. L., 2023. Review of rupture morphology of seismic faults. World Earthquake Engineering, 39(1): 28−37. (in Chinese) Ahmadi M. , Moosavi M. , Jafari M. K. , 2017. Water content effect on the fault rupture propagation through wet soil-using direct shear tests. In: Ferrari A. , Laloui L. , eds. , Advances in Laboratory Testing and Modelling of Soils and Shales (ATMSS). Cham: Springer, 131−138. Ahmadi M., Moosavi M., Jafari M. K., 2018a. Experimental investigation of reverse fault rupture propagation through cohesive granular soils. Geomechanics for Energy and the Environment, 14: 61−65. doi: 10.1016/j.gete.2018.04.004 Ahmadi M., Moosavi M., Jafari M. K., 2018b. Experimental investigation of reverse fault rupture propagation through wet granular soil. Engineering Geology, 239: 229−240. doi: 10.1016/j.enggeo.2018.03.032 Asano K. , Iwata T. , 2016. Source rupture processes of the foreshock and mainshock in the 2016 Kumamoto earthquake sequence estimated from the kinematic waveform inversion of strong motion data. Earth, Planets and Space, 68 (1): 147. Emmons R. C., 1969. Strike-slip rupture patterns in sand models. Tectonophysics, 7(1): 71−87. doi: 10.1016/0040-1951(69)90065-1 Johansson J., Konagai K., 2004. Fault induced permanent ground deformations−simulations and experimental verification. In: Proceedings of the 13th World Conference on Earthquake Engineering. Vancouver: Canadian Association for Earthquake Engineering, 1−15. Johansson J., Konagai K., 2006. Fault induced permanent ground deformations−an experimental comparison of wet and dry soil and implications for buried structures. Soil Dynamics and Earthquake Engineering, 26(1): 45−53. doi: 10.1016/j.soildyn.2005.08.003 Kubo H. , Suzuki W. , Aoi S. , et al. , 2016. Source rupture processes of the 2016 Kumamoto, Japan, earthquakes estimated from strong-motion waveforms. Earth, Planets and Space, 68 (1): 161. Lee J. W., Hamada M., 2005. An experimental study on earthquake fault rupture propagation through a sandy soil deposit. Structural Engineering, 22(1): 1s−13s. doi: 10.2208/jsceseee.22.1s Lee Y. H., Hsieh M. L., Lu S. D., et al., 2003. Slip vectors of the surface rupture of the 1999 Chi-Chi earthquake, western Taiwan. Journal of Structural Geology, 25(11): 1917−1931. doi: 10.1016/S0191-8141(03)00039-7 Ma K. F. , Lee C. T. , Tsai Y. B. , et al. , 1999. The Chi-Chi, Taiwan earthquake: large surface displacements on an inland thrust fault. Eos, Transactions American Geophysical Union, 80 (50): 605−611. Sanford A. R., 1959. Analytical and experimental study of simple geologic structures. GSA Bulletin, 70(1): 19−52. doi: 10.1130/0016-7606(1959)70[19:AAESOS]2.0.CO;2