Study Of Construction Deformation Mechanism And Conrolling Methods For High Cutting Slope Projects

Based on the construction of high cutting slope in North-Guangdong Section of BeiJing-Zhuhai Expressway (Xiaotang-Gantang section), this paper presents an approach to establish slope structure. And on the basis of investigation and summation for large amount of geological condition and slope geological structure of high cutting slopes, four typical high cutting geological slopes (which are thick sandstone stratum, stratum including weak coal, stratum made of red or brown plastic clay and soft rock mass and stratum made of remnants rock mass) are selected to study and establish responsive slope models. On the basis of structural model, this paper studies the theory and approaches of deformation control for high cutting slopes, and through theoretical researching, numerical analyzing, geological mechanical model tests and analysis for field test results, comes to the conclusions as follows:1. On the basis of geological investigation for large amount of high cutting slopes at Worksite 144 in BeiJing-ZhuHai Expressway, the principal geological characteristics of various slope structures and the chief factor affecting the stability of excavating slopes are summarized and studied in terms of its categaory. The concept of slope structure is presented, and the approach to establish the slope structure, as well as the method analyzing the stability of slope structure through establishing the geological mechanical models, are put forward. Stability analyzing methods which takes the slope structures and the construction process into account are presented, and provide a new method and a proper research direction for high slopes stability analysis of expressway construction at complicated mountainous area.2. According to the analysis of stress field and displacement field as the result of cutting and unloading process, affected zone by cutting in the slope is provided. In the effected zone of the slope, relaxation zone will be varied if corresponding safety factor if varied. In other words, the process of analyzing relaxation zone related to one safety factor can also be regarded as the process of searching potential slide surface related to the same safety factor. Elastic wedge model is used for analysis of relaxation zone of cutting homogeneous slope. The relaxation zone at process ofcutting can be calculated according to elastic plane-strain theory, and it is interpreted by an example.3. Numerical analysis method of relaxation zone is provided and its procedure by analyzing stress field or displacement field is given in detail by some practical high rock slope projects. Analysis results of relaxation zone of four typical worksites corresponding to foregoing four slope geological structures are presented.4. The study for the relaxation zone of high cutting slope on worksite K98 adopts geological model test. By comparison, deformation principle deriving from the test results coincide with the results of corresponding theoretical and numerical analysis, and that validates the reasonability and practicability of the theory and numerical method for analyzing the relaxation zone of high cutting slope which is introduced in this paper.5. A integrated construction method (including reasonable construction procedures ,principles, optimize for construction method, information construction technique and pre-reinforcement technology, etc) are summed up. A example successfully applying information construction method to supporting project ispresented.6. Large amount of field test data from many field test sites of high cutting slope in the field test projects is cumulated and analyzed, that include data for loading of anchor-cable, stress of main rode in pile, stress of back-pile, deep hole inclinometer data and displacement measurement data, etc. The result shows that, as an important part of information construction technique, field test can not only evaluate the stabilization of slope and validate the effect of stabilize in time, but also can feed back the results of test to design and construction, and so that to improve designing an...