New integrated analysis method to analyze stress regime of engineering area

An integrated analysis method (IAM) for how to accurately determine the stress regime of an engineering area is presented, which utilizes the faulting mechanical analysis method, in-situ stress measurement and numerical modeling technologies to determine the stress regime comprehensively to draw a reliable conclusion. The faulting mechanical analysis method and in-situ stress measurement techniques can support and verify each other mutually, and offer basis for the numerical model. Moreover, the numerical modeling can help understand the influences of geological conditions on the measured data. At the same time, the numerical model can reveal a 3-D distribution of stress regime. A case is demonstrated to prove the efficiency of this method. This engineering area is located in the Shandong Peninsula, and tectonically controlled by the sub-EW late Pleistocene active faults. The geotechnical investigations show that almost all the small regional faults are nearly EW and dip by 65-85 degrees. According to the faulting mechanical analysis method, the relationship among the three principal stresses should be S_H> S_V> S_h, and the direction of the S_H should be N60ºE-N120ºE. The in-situ stress measurements indicate that the stress state is favorable for strike-slip faults, and the orientation of S_H is N66.6~87.6癢. Both conclusions agree well with the data shown by the World Stress Map. One numerical model based on laboratory tests and geotechnical investigation results is set up to simulate the stress regime of this engineering area. The numerical modeling results are consistent with the in-situ stress measurements. At the same time, the numerical modeling and the geotechnical investigations show that some measured data are affected by the small regional faults remarkably. The results of the numerical modeling can reflect the stress regime of intact rock mass.