The Excavation Numerical Simulation And Dynamic Characteristics For Neighburhood Tunnel

In recent years, with the rapid development of expressway construction inmountain areas, Neighburhood tunnel has become a main kind of structure form, andit has several features, such as the independent construction for two tunnels, the lowercost of construction, and beautiful appearance etc. Due to the small distance betweenthe tunels, the force conditions of the tunnel liner and its surrounding rock (especiallythe middle rock pillar) are even more complicated, thus, studying in this respectduring the process of design and construction is indispensable.In this paper, choosing the DaiYuLing No.2tunnel of Zhuang-Gai expressway inLiaoning Province as the project background, we perform the analysis and research onthe mechanical characteristics and stability by the numerical simulation during theconstruction process of neighburhood tunnel.1. Getting some basic information by means of test, observation etc, then,determining the mechanical parameters of rock masses by Hoek-Brown Criterion.2. Setting up the3-D numerical simulation models for Surrounding Rock of Ⅲand Ⅳ respectively, and simulating the actual excavate process by using the finiteelement analysis software ANSYS with the function of "element KILL and ALIVE".According to different surrounding classes and different construction processes,analyzing the change rule of stress field and displacement field about the tunnelssurrounding rock. Basing on the analysis, the most unfavorable position of the tunnelunder load and the reasonable construction methods for Surrounding Rock of Ⅲ andⅣ respectively have been found. In addition, through comparing the results of thenumerical simulation with the actual monitoring data, it can confirm the accuracy ofthe numerical simulation method.3. To the neighborhood tunnel on particular geological conditions, setting up theplane strain finite element analysis, and studying on the displacement, stress and thestress characteristic of support structure of tunnel and surrounding rock, the effect oftunnel depth and bias on the stability of neighborhood tunnel is given.4. Taking advantage of the transient-dynamic fundamental, building2-D modelwith ANSYS, according to different situations, such as different surrounding classes,different distance among tunnels, different constructions etc, analyzing the affectionof the exploding and excavating during the new tunnel building to the tunnel which already have been finished. Besides, analyzing deeply in different aspects (vibrationvelocity, stress field etc), the relationship between both the tunnel spacing, excavationmethods and the vibratory response of tunnel liner is pointed out in this paper.