Investigation and modeling of deformation structures on ground surface caused by fault rupturing

一般来说，抗震设计方法通常考虑地震振动引起的结构破坏和液化引起的地面运动。但在1999年土耳其Cokaeri地震和台湾Chi-Chi地震中，出现了严重的工程结构断裂危险。因此，本研究的重点是断层破裂危险的缓解技术。2001年，提出了一种利用活动断层上不完备表面层缓冲作用的减灾措施新思路。设计了各种形式的地面改善方法。本发明是一种新型地基改良方法，申请专利号：2001-316161。2002年，进行了一系列物理模型试验和数值分析。结果表明，由吸收层和刚性梁层组成的改进地基具有显著的性能。此外，刚性梁层的抗弯刚度和锚杆位置是一些重要的设计参数。2003年，通过模型试验研究了倾滑断层的适当锚固位置。提出了将刚性梁层假设为弹性梁的设计计算方法。通过模拟试验结果的试验计算，验证了该设计模型能够较好地预测改良地基的性能。最后，对铁路车辆穿越走滑断层的原型行为进行了计算。计算结果表明，提出的地基改善方法对降低铁路设施结构损伤效果显著。

In general, earthquake resistance design methods typically thke into account the structural failures by earthquake vibration and ground movements by liquefaction. However, serious fault rupture hazards on engineering structures were seen in Cokaeri earthquake, Turkey, and Chi-Chi earthquake, Taiwan, in 1999. Thus, this study focuses on mitigation technology for fault rupture hazards.In 2001, a novel idea of mitigation measures was proposed that utilized the cushion effect of incompetent surface layer above active faults. Various forms of ground improvement methods were devised. This invention was patented claiming as a new ground improvement method, Application No.2001-316161.In 2002, a series of physical model tests and numerical analyses were conducted. The results demonstrated that the improved ground comprised of an absorption layer and a rigid beam layer showed remarkable performance. Furthermore, flexural rigidity of the rigid beam layer and locations of anchors were proved to be some of the important design parameters.In 2003, appropriate locations of anchors were investigated for dip-slip faults by the model tests. Design calculation method was also devised assuming the rigid beam layer as elastic beam resting on Whinkler's springs. Then, some trial calculations simulating the experimental results proved that this design model was adequate in predicting the behaviors of the improved ground. Finally, and attempt was made to calculate the prototype behavior assuming a railway truck crossing strike-slip fault. The computed results demonstrated that the proposed ground improvement method was effective in reducing the structural damages on the railway facilities significantly.