Applied Mechanics and Materials Vols. 405-408

Abstract: Based on the characteristics of the Metro Operation System and the types of accidents, linked with Metro Operation Emergency Management System, this thesis develops a System of Metro Emergency Management Capacity Evaluation Index. Whats more, with the application of Analytic Hierarchy Process (AHP) and Fuzzy Comprehensive Evaluation (FCE), it also sets up the Metro Emergency Management Capacity Evaluation Model AHP - FCE Comprehensive Evaluation Model. Finally, the model comprehensively evaluates the ability of the domestic Metro Operation Emergency Management System. By analyzing the evaluation results, the author finds out the vulnerable spots of the system and puts forward his own opinions for improvement.

Abstract: Expatiate the forms of underground cavities extending section. Express the character and application range of every form. The stress-strain states of rock around garage, in each form at each step, were defined through carry out numerical simulation by using the ANSYS program.

Abstract: The waterproofing is the most essential technical specification and the difficult problem in civil engineering specially in the water draining water construction and the tunnel. Formerly, we used guard against infiltrate the concrete or in guard against the aqueous phase union with the outside waterproofing two defense lines, the effect actually not entirely as desired. In this paper, through combining engineering practice, raise a processing project of tunnel waterproofing constructions, based on the rigid-soft combination principle.

Abstract: This paper focuses on the surface settlement time lag caused by shield tunneling in sandy-pebble stratum in Chengdu. A surface collapse case during Chengdu metro construction was introduced and the mechanism of surface settlement time lag was analyzed. The process of the ground settlement was simulated using the UDEC software. It is found that: 1) over-excavation and the grouting failure are the root causes of surface settlement; 2) characteristics of the sandy-pebble stratum in Chengdu induce ground voids behind tunnel segmental lining; 3) the mechanism of surface settlement time lag can be explained by temporary ground arch in the sandy-pebble stratum.

Abstract: Problems often exist in construction of transportation tunnels, such as the effect of new tunnels constructed close to existing structures. Solving this magnificent problem by carefully choosing tunnel construction methods will be beneficial to minimize effects on existing structures while ensuring the newly constructed tunnel is both time-consuming and economical. Three representative engineering methods-the benching tunneling method, the Center Diaphragm method and the Cross Diaphragm method-are compared in controlling the settlement of new tunnel vault and the deformation of the existing tunnel. Finally checking the simulation results by comparing with field measurement data.

Abstract: A model test was performed to investigate the impact of active ground fissure on metro tunnel. The test results show that under the action of active ground fissure, the metro tunnel behaviors as a cantilever elastic foundation beam, and the top is in tension and its bottom is in compression. The tensile parts are located in the foot-wall with the range 0.75～2.33D（D is tunnel diameter） distance from active ground fissure and the compressive parts are mainly located in the foot-wall with the range 3D distance from the fissure. When the settlement of hanging wall of ground fissure reaches 1cm（25cm in prototype）, the tunnel bottom appear cavity in the hanging wall and cracks in the foot-wall. With the settlement development of the hanging wall of active ground fissure the vertical soil pressure on the top of tunnel greatly increases and reduces at the bottom of tunnel in the hanging wall.

Abstract: According to the standard Specification for Design of Hydraulic Tunnels (DL/T 5195-2004), the free-flow tunnel lining structure should be calculated with beam element of finite element method that based on structural mechanics. However, the practical calculation shows that when the lining structure reaches a certain thickness, the beam element calculation results are no longer accurate. Combining with the engineering example, stress and internal force of lining structure with different thickness were calculated by using beam3 beam element and the solid65 element respectively in frame beam analysis. Differences analysis shows that the solid element is better than beam element in calculation. The influence of solid elements grid size on the result accuracy was conducted, and used to amend the calculation result of the solid element, which provides a certain reference on choosing the right element in the similar projects or structure simulation.

Abstract: With the development of global urbanization, the development of underground rail traffic network is imperative, and the subway has become a convenient and effective traffic tool to solve people’s trip. While the subway accidents happen constantly, so the subway emergency rescue has become an important event to related departments. This paper firstly analyzes the main types and characteristics of subway emergencies, and concludes some main emergency countermeasures.

Abstract: The tunnel construction causes deformation, even damage of the nearby buildings and other types of structures. Using 3d finite element method can simulate the process of shield tunneling construction. The paper studies the influence of different building load on the deformation of soil, when considering different excavation steps in the process of tunnel construction. The results show that the building load has important influence on the surface displacement during the construction of tunnel. With the advancement of excavation, sedimentation tank will move forward and become larger. By the influence of jacking force, the soil and rock in front of tunnel face moves forward and upward, thus forming the surface uplift.

Abstract: The monitoring measurement on-site, which monitors the stability of surrounding rock and tests the rationality of design, is an indispensable mean. In the process of construction, the Zhang Jiaqu tunnel is open, by monitoring the whole section, guiding and determining the construction time of secondary lining and mastering the working state of primary supporting. This paper introduces the main content of monitoring measurement and analyzes the monitoring data, so as to provide the reference for similar projects.