The effect of soil cohesion and friction angles on reverse faults

Severe faults have caused many earthquakes around the world throughout history. More recently, earthquakes have occurred in Taiwan, China (Chi-Chi fault), and elsewhere, causing loss of lives and destroying many buildings and structures. These tectonic movements have gained attention from engineers, and in the past 15 years, the focus has been on faulting mechanisms. In this study, a physical model (1 g) was fabricated and used to evaluate the impact of a reverse fault in a field with a tunnel. In the 1 g model, researchers installed additional gauges on the tunnel, so that all the displacements could be adjusted, and all the responses could be monitored during faulting. An experimental study of various soil properties (cohesion and friction angles) in reverse faults on the tunnel lining were carried out and are described herein. A comparison of results for different levels of soil cohesion revealed that it can dramatically reduce the displacement by as much as 40%, and that friction angles of 27° can record approximately 60% more displacements than at 37°. Furthermore, a comparison of fault angles of 30° and 60° indicates that the displacements can be different by more than 43% in cohesionless soil and about 64% for a friction angle of 27°

A novel experimental study on the effects of soil and faults properties on tunnels induced by normal and reverse faults

Due to the world population increasing considerably, there is a need for efficient public transportation, such as the subway. However, it has become a major concern to geotechnical engineers that the development and construction of subways are held underground where faults exist, as it will be a major risk to any structure if the fault is still active. Several seismic events, such as the earthquakes in Taiwan in 1999, China in 2008, and Malaysia (Sabah) in 2015, caused by fault ruptures, signify the importance of this study. In this paper, a physical model of 1000 mm in height, 3000 mm in length, and 1000 mm in width, which is the largest single gravity (1g) model for simulation faults (normal and reverse) ever built, was fabricated to evaluate the influence of various soil properties, various fault angles, and tunnel depths on tunnels affected by normal and reverse faults. The effects of various soil properties, such as water content, particle size, cohesion, and friction angle, had revealed major changes (approximately by 34%, 39%, 64%, and 39%, respectively) in tunnel displacements. Results also showed that increasing of fault angle could increase the tunnel displacement as much as two times. In addition, when a tunnel is located close to the ground surface, 22% less displacement was found to have occurred to the tunnel. With the results obtained from the physical model, simulation had been made using plane strain and axial symmetry (PLAXIS) software. The comparison made between rock and soft soil showed that soft soil imposed two times more displacements than rock, and an existence of foundation in soft soil and rock can decrease the tunnel displacements by 6% and 4%, respectively. This paper asserts that besides the structural design of a tunnel, the geotechnical design also has a major impact on the safety and robustness of the tunnel, in which aspects such as soil properties, tunnel depth, and fault angle have a strong influence on tunnel damages which were not considered in previous research, despite their importance

Rescue of platinum-damaged oocytes from programmed cell death through inactivation of the p53 family signaling network

Non-proliferating oocytes within avascular regions of the ovary are exquisitely susceptible to chemotherapy. Early menopause and sterility are unintended consequences of chemotherapy, and efforts to understand the oocyte apoptotic pathway may provide new targets for mitigating this outcome. Recently, the c-Abl kinase inhibitor imatinib mesylate (imatinib) has become the focus of research as a fertoprotective drug against cisplatin. However, the mechanism by which imatinib protects oocytes is not fully understood, and reports of the drug's efficacy have been contradictory. Using in vitro culture and subrenal grafting of mouse ovaries, we demonstrated that imatinib inhibits the cisplatin-induced apoptosis of oocytes within primordial follicles. We found that, before apoptosis, cisplatin induces c-Abl and TAp73 expression in the oocyte. Oocytes undergoing apoptosis showed downregulation of TAp63 and upregulation of Bax. While imatinib was unable to block cisplatin-induced DNA damage and damage response, such as the upregulation of p53, imatinib inhibited the cisplatin-induced nuclear accumulation of c-Abl/TAp73 and the subsequent downregulation of TAp63 and upregulation of Bax, thereby abrogating oocyte cell death. Surprisingly, the conditional deletion of Trp63, but not ΔNp63, in oocytes inhibited apoptosis, as well as the accumulation of c-Abl and TAp73 caused by cisplatin. These data suggest that TAp63 is the master regulator of cisplatin-induced oocyte death. The expression kinetics of TAp63, c-Abl and TAp73 suggest that cisplatin activates TAp63-dependent expression of c-Abl and TAp73 and, in turn, the activation of TAp73 by c-Abl-induced BAX expression. Our findings indicate that imatinib protects oocytes from cisplatin-induced cell death by inhibiting c-Abl kinase, which would otherwise activate TAp73-BAX-mediated apoptosis. Thus, imatinib and other c-Abl kinase inhibitors provide an intriguing new way to halt cisplatin-induced oocyte death in early follicles and perhaps conserve the endocrine function of the ovary against chemotherapy.Cell Death and Differentiation advance online publication, 19 April 2013; doi:10.1038/cdd.2013.31