Research On The Long-term Stability Of Ⅱ-7 Slope At Tangtun Section Of Tong Huang Highway In Anhui Province

A long-term stable slope means relative supporting structure won’t be damaged or slope creep value has little influence on construction’s functions and normal working, which is being studied in Tong-Huang highway Tang-Tun section II-7 slope located in southern gate of Huangshan in Anhui province. This section is an important access to Tangkou town in Huangshan. If the slope failed, it would have very bad influence on the safety of highway and cause great lose. So there’s great value studying the long-term stability of the slope, and it’s meaningful to supporting design. The long-term stability problems of the slope are studied started with analyzing geological data, monitoring data and rainfall information.Analyzing geological data is at first, and studying the deformation pattern and formation mechanism to summarize inner factor of deformation. Analyzing monitoring data to deeper analyze the influences caused by rock creep, rainfall and anchor stress. Establish a model of slope deformation and anchor stress, and calculating its parameters with Matlab, which can predict deformation value and increase of anchor stress. Then works as follows have been done: analyzing whether the anchor would be broke and be stretched out from rock or not, which can be predict out with anchor stress value; Figuring out sliding time with Saito model based on slope deformation value; establishing a creep model of ground parameters of slope slip band with aging theory; figuring long-term stability coefficient with ultimate equilibrium theory; and analyzed long-term strength of anchor in different corrosions. Evaluating the long-term stability of II-7 slope section with above methods in the end, and conclusions as follows:(1) Slope deformation in construction period is mainly affected by excavation and rainfall. Rock creep, rainfall and anchor stress changes in run-time.(2) Slip mass near main sliding section is thicker and supporting strength is weaker. Main sliding mass deforms fastest during run-time and increment of anchor stress is the largest.(3) Anchor stress reaches 1300 k N at larger deflection part in 50 years at the year of 2057 during working period, which is beyond design value for 460 k N. Anchor deflection reaches 167.40 mm which is 72.11% of its ultimate strength. And the anchors will be parted at free section after working for 49 years under corrosion environment and pre-stressing.(4) The slope is stable to almost stable in the 10 years after supporting. And it is almost stable to under-stable in 20 to 30 years, under-stable in 30 to 50 working years. And the conclusion that the slope won’t failure of creep in 50 years, after figuring with Saito model and considering the most disadvantage factors is given out.