In order to realize the geostress state of a new pattern hydroelectric project in southwest china, demonstrate the scheme design of the air-cushion surge tank for the hydroelectric project, the hydraulic fracturing technology has been adopted to define the In-situ stress and related rock mechanics parameters of rock mass around the high pressure cavern, and utilizes the data of stress measurements, together with numerical simulation and regression analysis to synthetically analyze the ground stress field at engineering sites. The results show that the direction of maximum principle stress at engineering sites is N33°∼52°W, the elevation is N26°∼39°W, the value is 7.35∼8.16MPa; that the maximum principal stress in the rock mass around the high-pressure cavern is 10.63MPa, the minimum principal stress is 4.45MPa, The tensile strength is about 4.4∼8.6MPa, the permeability under the pressure of 3∼5.0MPa is less than 2.0 Lu; the jacking strength is <1.0∼5.5MPa. In the main the rock mass suit the air-cushion surge tank. Whereas the rock of the vertical bore at the air-cushion surge tank is fragmentation, It is suggested that increasing the depth of the cavern in order to enhance carrying capacity of the rock. In addition there exist some tensile fissures in the rock mass of high-pressure cavern, which have poor bearing strength, good connectivity and severe water permeability, and which are a huge hidden trouble for the non-supported high-pressure cavern construction. The effective high-pressure grouting measures shall improve the integrity of rock mass structures and enhance the high-pressure sealing function, which is a key point for the establishment of the project.
The people use the hydro-energy resources already near millennium, and using hydraulic electro generating also had hundred years in history.