The Numerical Simulation Analytical Study On The Construction Method And Dynamic Response For The Long-span Tunnel

In company with nonstop rushing of the long-span tunnel construction, a matter station encounter more and more. For instance, the demand of the present design and construction code is already insatiability with the need of long-span tunnel engineering design and construction. And both domestic and foreign concerned research output is not too much to refer. So the engineering design and construction on long-span tunnel has definite blindness of the approve use for reference. Consequently, it was for the present urgency problem on that how about increase in advance quality on the engineering design and construction of the long-span tunnel. The key to solve this matter is making research direct towards on excavation and support course of the long-span tunnel. The excavation and support systematic mechanics character information of long-span tunnel surrounding rock under the course of different construction method is achieved to supply design basis and supervise for the long-span tunnel. For this reason, in the thesis, the numeric value on the construction method of the long-span tunnel is simulated and the explosion earthquake dynamic response of tunnel is analytical studied. And this research possesses not only theoretical value, but also important engineering sense as well.Based on the research output of predecessor, in the thesis, with Yanqianshan No.2 long-span tunnel (23.32m) for subject investigated, the long-span tunnel construction method numeric value is simulated with the plasto-elasticity theory, dynamic principle and the numerical analysis method. And the explosion earthquake dynamic response on tunnel is studied. Mostly acquisition research output as follow:1. The plasto-elasticity and finite element method elementary theory is used to create Yanqianshan No.2 tunnel plane elasto-plasticity finite element model and elasto-plastic yielding criteria. Handling elasto-plastic finite element method and adopting ANSYS software, the tunnel excavation method construction course which adopt the center diagram method and center cross diagram method and both side drift method for V -level surrounding rock is simulated with dynamic numerical as well. And surrounding rock stress field, displacement field, bending moment, shearing force and ax force variation conditions is gained during excavation on all step of three construction methods. The detailed analyse is done for calculation output. At the same time the safety and economy is generally considered. The CRD construction method is adopted Yanqianshan No.2 tunnel for scientific reasonable. Consequently, the research output and conclusion is supplied for design basis and supervise for construction of Yanqianshan No. 2 tunnel.2. Handling plasto-elasticity, structural dynamics and numeric value analysis method, the tunnel surrounding rock and support structural dynamic response is researched under the action of demolish load. Which show that: during construction of smallness clear distance tunnel, the demolish excavation backing of constructional tunnel should effective mostly priority constructional tunnel. The influence maximal region is the blast front side of priority constructional tunnel. The peak value velocity and accelerated velocity of blast front side is far several fold from which of far distance blast, furthermore, the explode front side peak value displacement is greater than that of far blast. It explanation that in the course of construction, the blast front side is vulnerable region of demolish excavation controlling, and Respond explode front side is attached importance to monitor for lever heading velocity. The stress of all tunnel characteristic points is far smaller than the ultimate bearing pressure of the surrounding rock structure, and the conclusion which the influence of demolish stress for surrounding rock liner structure is small can be drawn. The primary support facility of priority constructional tunnel has definite effect for blast controlling, especially in the lower-level surrounding rock. Before advanced construct tunnel demolish excavation, priority constructional tunnel should be support to form sealing, favor for reducing of blast vibration influence.3. Based on the mechanical characteristics of the heavy section member in bending in the surrounding wall whose thickness is third of grotto span under the crossrange explode load and the conclusion about the free field stress state is basically approached outside of surrounding rock, and with massive plate theoretical under external applied load of free field stress, the solution can be given. Consequently, the dynamic interaction between substructure and surrounding rock, the member in bending dynamic range with representing separately liner and dielectric based on lamella and massive plate theoretical can be described. The contact pressure function q(x, t) is used to contact with the interaction force between the surrounding rock and liner. Through the volume of solution simultaneousness equation, the analytic solution about straight wall invert line dynamical of the given elastic half-space interaction effect is applied, and analytic solution of expression on function q(x, t) is listed.