The Secondary Excavation Stability Analysis Of The Existing High Slope And Engineering Technology Research In The Highway Reconstruction Project

In the 1990 s the highway construction in China has entered a rapid development period, in recent years, with the economy and traffic volume increasing, the highway must be renovated. In this kind of project, the secondary excavation construction of the existing high slope has such characteristics: long duration, the high construction difficulty and the great influence on highway operation. This research was based on the Hui Shen highway, by the way of the field investigation and theoretical analysis, and numerical simulation, and its main results are as follows:(1) By investigation the regional environment, the information of high slope was preliminarily mastered, whether it is the existing or the secondary excavation. Its size, geology, disease and the protection form were known during the construction process.(2) Based on the above-mentioned information, the K22 + 220 ~ K22 + 460(left) high slope was chosen as the typical one. By analyzing the influence factors of the secondary excavation of the typical slope stability, its damage mode was “slip-pulled crack”, and calculate the safety factor of the two potential fracture surface in the slope.(3) Aiming at the secondary excavation of the existing high slope, the safety factor of different excavation stages and the changing rule of the stress and strain are the main purpose of this study, by using the method of numerical simulation. The results show that, along with the excavation, the shear stress concentrate on the slope toe, and the tensile stress to the top area; meanwhile the plastic zone initially occur on the structural plane, and gradually to the whole slope; the shape of fracture plane are the combination of circular arc surface and plane.(4)Because of the specificity of the secondary excavation, the construction principle and technology have been put forward which are appropriate for the existing slope, and information construction and drainage system contribute to reduce the security hidden danger.