Excavation Unloading Mechanical Properties Of Rock Slope And Its Hydraulic Engineering Application

The country’s new energy development strategy and the huge investment in agri-culture and water resources promote the development and construction of water con-servancy and hydropower projects. In the course of the construction of the water con-servancy and hydropower engineering which are inevitably encounter the problemsabout rock mass excavation and slope stability. Rock mass excavation is a kind of un-loading from the point of mechanics analysis, but the mechanical parameters of rockmass is widely used in the present analysis and design is obtained in the traditionalloading test conditions, use these mechanical parameters obtained by loading test toanalyze the problem of excavation unloading, there are differences between the resultsobtained with the actual situation, may lead to safety hazards and accidents. Accordingto the characteristics of water conservancy engineering, it is meaningful and valuablefor the design and construction of hydropower engineering to research and analysismechanical properties of rock slope excavation unloading, and seek a kind of conve-nient theory and numerical methods which considering the unloading effect to analysisand calculate the stability of rock slope excavation engineering. In order to solve thisproblem, this article relies on the study and analysis from theoretical derivation, numer-ical analysis, calculation and analysis for practical engineering, related research and soon, the main research contents and results are as follows:①According to the geological condition and engineering characteristics for therock slope of water conservancy project, based on the elastic mechanics theory, estab-lished the tensile plane model with cracks for excavation and unloading rock mass, de-duced the equivalent modulus of rock mass during the opening stages of the mi-cro-cracks.②Discussed the relationship between the equivalent modulus and tensile stressfrom D-M model based on fracture mechanics. Under the condition of Mohr-Coulombstrength criterion, deduced and qualitatively judged the change rule of strength parame-ters when rock mass in the process of excavation unloading.③According to the theory of fracture mechanics, researched the influence betweencracks and mechanical properties of rock mass, and obtained relationship between thecrack size, crack distribution and equivalent modulus by theoretical and finite elementmethods, analyzed the impact regulation of two kinds of crack distribution on the rigid- ity of rock mass.④The results is applied in water conservancy project on the left bank of JinfoMountain slope excavation simulation, and researched the finite element numerical me-thod considering the effect of rock mass excavation unloading, compared with the con-ventional calculation results, and provided the reasonable suggestion and reference forthe design and construction of similar projects.