The Study On The Rheology Of Soft Rock And Surrounding Rock Support

The soft rock tunnel project increases gradually, and the construction technology of the soft rock tunnel has been greatly developed and significantly improved with the high-speed development of traffic construction in our country. Rheology is the intrinsic characteristic of the soft rock. For rheological phenomena exist in various soft rock projects, the various effects brought by the rheological phenomena has been recognized by many people. In the tunnel projects, the soft surrounding rock of stability related to the project quality and safety of staff. According to the surrounding rock its own conditions and engineering geological environment, it have a very important practical significance to choose reasonable and effective support method, reduce the deformation of soft surrounding rock, control and reduce the adverse effects of rheology for ensuring the stability of surrounding rock.The engineering properties of soft rock and its rheological constitutive and organic which been combined with the study of the characteristics of soft rock of You Shui Tunnel have been studied on the foundation of some research results in this paper. The factors affecting the stability of soft surrounding rock and its destruction of the form have been analyzed. Under the guidance of New Austrian Tunneling method, according to the various properties of soft surrounding rock, they have been studied about the specific supporting principles of soft rock tunnels and stability analysis methods of soft surrounding rock. There are many support ways, in order to further studying for soft surrounding rock support method, and improving the stability of surrounding rock, physical model test method have been used to make You Shui Tunnel as research prototype, by using comparative analysis method, making two different supporting ways(both ways are all using steel nets and spraying concrete, the difference is the one of two increased the anchor grouting)put in two tunnel model, which they have nearly the same physical and mechanical properties and sizes, and under the conditions of level-loading at the same time, measurement and analysis of the data have been used to determine what kind of supporting more effective in reducing the deformation of surrounding rock, so that to ensure the stability of surrounding rock. Second, under the condition of long-term stable load, recording and analysis of surrounding rock deformation coursed by the influence of creep at the same time period. Some laws of soft rock creep have been studied by using data processing. The effect of supporting about the controlling on the surrounding rock creep, and the two different supports in the controlling effect of surrounding rock creep have been compared and analyzed.The result shows that the soft surrounding rock of You Shui Tunnel have a complex character, it have difficulties on supporting surrounding rock, it is not enough to maintain the stability of surrounding rock only with the anchor gushes. In order to make the surrounding rock get a stability condition, it must adopt grouting, use of the bolting and grouting support.For the weak surrounding rock itself, its top of the surrounding rock is usually more vulnerable than the both sides of surrounding rock on deformation, both on deformation faster and larger. So in the design of supporting, it must be ensuring the stability of the top of surrounding rock first, and the bolting and grouting support would be able to do this well. In supporting the soft surrounding rock, the grouting not only improve the strength of rock, effective use of the carrying capacity of the surrounding rock itself, reduces the pressure on supporting, but also make the surrounding rock and bolt more integrity, offers a great foundation for the surrounding rock, this will make the support structure and the surrounding rock to achieve co-load and co-deformation, and effectively control the surrounding rock deformation and deformation rate. Since bolting and grouting support itself has a higher solid load-bearing capacity, it can provide the necessary conditions for improving the strength of surrounding rock, and give full play to their own self-bearing capacity of surrounding rock. Even in the larger external loads, it can still be able to maintain the stability of surrounding rock. Besides of this, bolting and grouting support also play a good role in controlling and stabilizing the soft surrounding rock creep. The grouting fill the cracks, make up the defects of rock crystal, inhibited the rate and deformation of creep fundamentally, and so the total amount of creep and rate are significantly reduced, and the creep have been made into a stable state as soon as possible, It have been reduced also that the time of adverse influence on the stability of surrounding rock because of creep.