In-situ stress is the natural pre-existing stress confined in the rock before it is drilled, excavated or affected by outside influences. The in-situ stresses originate in the earth crust due to different factors, mainly the weight of the overlaying rock layers and tectonic movements (see Figure 1). The other factors are summarized in Figure 2. The in-situ stress can vary within one rock mass from one location to another due to varying rock properties. It is important to determine the magnitude and direction of in-situ stresses before doing underground work or designing underground structures, see table 1 for their different applications. In-situ stress characterization is the science of estimating the stress magnitudes and determining the orientation of three principle stresses: maximum horizontal stress, minimum horizontal stress, and vertical stress. | In-situ stress is the natural pre-existing stress confined in the rock before it is drilled, excavated or affected by outside influences. The in-situ stresses originate in the earth crust due to different factors, mainly the weight of the overlaying rock layers and tectonic movements (see Figure 1). The other factors are summarized in Figure 2. The in-situ stress can vary within one rock mass from one location to another due to varying rock properties. It is important to determine the magnitude and direction of in-situ stresses before doing underground work or designing underground structures, see table 1 for their different applications. In-situ stress characterization is the science of estimating the stress magnitudes and determining the orientation of three principle stresses: maximum horizontal stress, minimum horizontal stress, and vertical stress. |