| Tongyu Tunnel, which is being constructed now, is currently one of the most deep-lying and longest tunnels in Chongqing. Its geological conditions are extremely complex. The high-geostress and related stability of surrounding rocks are its main problems of engineering geology. Closely combined with this large-scale-engineering practices, based on comprehensive illustration of geology condition for construction in the engineering rockmass, beginning with researches on the stress-field of rockmass at the project area, for the purpose of guiding construction and optimizing design, the forming reasons of high-geostress in rockmass have been explored and discussed, and deepening and detailed researches on related rockburst have been made in this paper.Besides, starting with surrounding rock classification, investigation, control and measurement on the spot as references, based on the deformation information of tunnel surrounding rock, several characteristic types of the tunnel surrounding deformation at the high-geostress areas have been put forward. The dependence between surrounding rock and other aspects such as geology, geostress, rockmass strength and construction methods etc has also been analyzed. In addition, prediction of deformation in the tunnel surrounding rock has been studied with the method of BP nervous network technology.In the end, by means of numerical value simulation technology by finite element, stability and excavation methods for the weak surrounding rocks have been appraised on the whole. Some reasonable excavation methods have been put forward. Supporting and protection action mechanism of leading anchor roles has also been slightly researched. |
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