| Landslide is a common geological disaster which brought a major threat on human lives and property. It is happened frequently in Zhenjiang region of Jiangsu province, especially caused by rainfall occupy most part of the total landslides. It connects to Xiashu Loess which widely distribute in Zhenjiang region, Xiashu Loess has special engineering geology characteristic.It is difference in dry and wet condition. Rainfall is on great impact of the stability of Xiashu Loess slope. Actual the engineering in Zhenjiang, this paper carried out a series of studies for the reinforced mechanism of Xiashu Loess slope and the optimize design of anchor.(1) Analyzed Zhenjiang Xiashu Loess's geological characteristics and landslide features. Xiashu loess strata were selected as researching target. Known the mechanism of anchorage bar in loess strata.Then two formulae were derived from two special mechanism of the anchorage bar transferring load that could calculate the anchor force. The formulae were used to direct the engineering practice.(2) When under a small load,shear stress of anchor rod is relatively small in the surrounding region of porthole,but below the porthole,the shear stress suddenly increases and reach maximum,with the departing from loading end,the shear stress gradually decreases and reaches zero at the loading far-end. Anchoring force is related to but not proportional to anchorage length,when the anchorage length reaches a fixed value, the increase of anchoring force is extremely 1imted with the increase of anchorage length.(3) By the method of numerical simulation test, study was made on the reinforcement mechanics of full-length-bonding single cable in Xiashu loess strata, and the curve figures of axial force,shear stress and axial stress distribution in reinforced body were obtained, and the affect of the parameter changes on the reinforcing traits were analyzed.(4) Anchoring parameters of slope of Lion hill in Zhenjiang are best selected using orthogonal design principle. The results show that the effects of anchoring parameters are different and remarkable according to horizontal deformation of slope. The order of the difference is, the effect of anchoring bolt length> anchoring bolt angle>the interval of anchoring bolt. The optimum parameters are obtained. They are, its length is 8 meters,its angle is 20°and its interval is 3.5meters. And verified the selected parameters are rationality. (5) Using the strength reduction of FLAC3D, analyzed the stability of Xiashu loess slope of Xijingudu under natural state, reforcement state and rainwater exists. Slope stability in a natural state is much better than when there has rain. In natural state, when reinforced the slope safety factor raised from 1.13 to 1.69, under rain the reinforced slope safety factor raised from 0.90 to 1.39. Which shows the anchor on the slope played a significant role in reinforce, and strengthening effective, but also verify the anchor reinforcement mechanism in front of the section. It also shows that the rain affected the stability of the slope significantly.(6) Preliminary simulated the Xiashu loess slope stability with cracks and swelling, obtained the relationship between swelling force and slope safety factor when cracks existed. When the swelling force is greater than 10kPa, the slope safety factor is rapidly reduced. |
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