Even Measuring Mechanical Behavior Arch Tunnel And Monitoring Study

The tunnel design has to meet the minimum spacing requirements in the specification under normal circumstances, but when the tunnel connects with integral roadbed or bridge, tunnel convergence is bound to be linear indicators, multi-constraints of the topography, geological conditions, there must be a connection lead, resulting in the roadbed or bridge transition from monolithic separate tunnel connections, especially in steep terrain,"chicken feet" zone of the spine and white, the upper and lower split twin bore tunnel is difficult to meet the high-grade highway adjacent to the tunnel the minimum spacing requirements. Double-arc tunnel meet the above to be arch tunnel program and has a strong advantage, gradually recognized by the general engineering sector. However, with double-arc tunnel in the actual project, but also exposed the many problems:the arch tunnel over a single, failed to do so for different surrounding rock conditions, using different construction methods; double-arc tunnel design roc computing; the construction process, the interaction between the two p k pressure is generally based on the experience value, and there is no clear theory of positive-hole construction and its impact on the wall are difficult to grasp; In addition, after the completion of the arch tunnel more, the problem is mainly concentrated in the wall, such as cracking in wall seepage water.As the basis of the Zhang Hua highway Ma Bu Chong double-arc tunnel, the research content includes followings:(1) Summarizes various sectional forms of double-arc tunnel existing in highway at home and abroad was made; and also analysis the pros and cons of all the sectional forms, sum up the double-arc tunnel construction methods and application conditions, generalize the construction、anti-bias、anti-water treatment and other technical measures of the mid-wall.(2) By summarizing a variety of rock pressure calculation method, combined with the arch of the characteristics of the tunnel itself, double-arc tunnel to collapse the arch curve and the calculated value of arch tunnel to loose pressure and arch tunnel through the calculation of the depth of buried criterion, the depth of tunnel, bias arched tunnel surrounding rock pressure calculation was studied.(3)Application of FLAC3D numerical software to simulate the entire arch tunnel construction process was made. By analysis of numerical results.i.e. stress field of double arch tunnel in surrounding rock, stress distribution of the support structure of and mid-wall in the construction process and the variation of double-arc tunnel were whole obtained(4) By situ monitoring of the arch tunnel, and the measured data and numerical simulation results were compared, further analysis of the arched tunnel surrounding rock stress changes was made, stress changes rule and stress distribution characteristics in lining and in mid-wall in the process of excavation, was disclosed.