Deformation Control Measures Research Of Soft Rock Tunnel With Large Deformation

According to the country’s requirement of developing the infrastructure and expanding domestic demand vigorously. In recent years, many tunnels project have been constructed in the mountainous areas in our country, at the same time, some special geological conditions are often encountered on the tunnel entrance, Such as broken rock、Crack growth、Shallow bias, sometimes landslide is also associated with.These complex geological conditions often become an important factor affecting tunnel safety, stability. So the SunJiaya tunnel being constructed is becoming the engineering background in this paper. Around the engineering properties which are peculiar to the landslide of shallow tunnel. Starting from the construction process, the deformation control of surrounding rock has been studied.The research contents and methods:(1) Selecting a section of the tunnel as the object of studying on the entrance respectively studying the surrounding rock deformation,surrounding rock pressure, stress of arch bridge, primary support stress and so on four aspects to analyze and summarize the stress-strain law of surrounding rock deformation(2) The changes of the tunnel above the landslide were monitored, mainly starting from two aspects to monitor, on the one hand:From the external anti-slide pile to monitor the landslide deformation, on the other hand:monitoring the soil of rock from the inclinometer hole within the landslide. Analyzing the monitored data and summarizing the deformation law of the landslide.(3) Creating a two-dimensional finite element model.Contrasting and Analyzing the Excavation section forms、different step height different anchor supports method to evaluate the situations of surrounding rock deformation and lining stress the value to find a reasonable Excavation and supporting method.(4)Creating a three-dimensional finite element model. The surrounding rock deformation and lining stress conditions on the step length of20m,30m,40m were analyzed to find the law on Rock deformation and lining stress change.The main research results:(1) Through analyzing the result of the tunnel monitored, the surrounding rock deformation and lining stress are seriously asymmetry. The surrounding deformation reaches maximum after the tunnel excavation15days later, and the stress in the lining of the construction increases faster after10days. The time that the surrounding rock deforms and the stress in lining changes are similar (2) Through the landslide monitoring analysis, the landslide slips much after the anti-slide pile. Constructed one month later, Affected by the tunnel construction and the rainfall much more, the landslide and bedrock rupture apparently.(3) Through two-dimensional simulation, the lateral wall Dao-Ken excavation method, steps excavation method on the deformation of the optimal control of sex, the characteristic of surrounding rock deformation in the condition of different step heights and different bolt support of the surrounding rock are concluded(4) Through the three dimensional simulation, it is concluded that the length of steps have effected on surrounding rock deformation and the stress of the lining, and how to control the stability of the tunnel through changing the length of the steps.