scholarly journals In situ stress measurement by the stress relief technique using a multi-component borehole instrument

2007 ◽  
Vol 59 (3) ◽  
pp. 133-139 ◽  
Author(s):  
Atsushi Mukai ◽  
Tsuneo Yamauchi ◽  
Hiroshi Ishii ◽  
Sigeo Matsumoto
Keyword(s):  
Stress Measurement ◽  
Stress Relief ◽  
In Situ Stress ◽  
In Situ Stress Measurement

Integrated Application of Three In Situ Stress Measurement Techniques

2011 ◽  
Vol 301-303 ◽  
pp. 949-953
Author(s):  
Yuan Li ◽  
Lan Qiao ◽  
Zhi Li Sui
Keyword(s):  
Acoustic Emission ◽  
Hydraulic Fracturing ◽  
Stress Measurement ◽  
Stress Relief ◽  
In Situ Stress ◽  
In Situ Stresses ◽  
In Situ Stress Measurement ◽  
Iron Mine ◽  
Acoustic Emission Test

The CSIRO overcoring stress relief and hydraulic fracturing methods are the most popular methods used for the measurement of in-situ stress at depth. One major advantage of the CSIRO overcoring stress relief method is that the three dimensional state of stress can be obtained, but the measurement must be done in an excavated tunnel[1]. Hydraulic fracturing method can be carried out on the ground surface, but it assumed that one of the principal stresses direction is vertical[2,3]. In terms of the disadvantages of the two methods, the techniques based on core orientation and acoustic emission behavior of rocks are incorporated in the in-situ stress measurement in order to obtain the in-situ stress conditions at depth in Shuichang Iron Mine. According to the comparison of the measurement data obtained from the acoustic emission test in the laboratory and CSIRO overcoring stress relief measurement in the field, effectiveness of the acoustic emission test is confirmed. In addition, the relationships between in-situ stresses and tectonic settings are analyzed. Finally, the distribution of in-situ stresses in Shuichang Iron Mine is given, which provides a meaningful guideline for the following mining and design.

scholarly journals Geological Core Ground Reorientation Technology Application on In Situ Stress Measurement of an Over-Kilometer-Deep Shaft

2020 ◽  
Vol 2020 ◽  
pp. 1-13
Author(s):  
Chunde Ma ◽  
Xibing Li ◽  
Jiangzhan Chen ◽  
Yanan Zhou ◽  
Sen Gao
Keyword(s):  
Principal Stress ◽  
Stress Measurement ◽  
Stress Relief ◽  
Maximum Principal Stress ◽  
In Situ Stress ◽  
Vertical Stress ◽  
Geometry Model ◽  
In Situ Stress Measurement ◽  
Stress Changes

As mining progresses to depth, engineering activities face the extreme challenge of high in situ stress. To efficiently measure the deep in situ stress before engineering excavation, an innovative deep in situ stress measurement method capable of the geological core ground reorientation technology and acoustic emission (AE) technology was proposed. With this method, nonorientation geological cores collected from the thousand-meter-deep borehole were reoriented based on the spatial spherical geometry model and borehole bending measurement principle. The distribution of deep in situ stress of an over-kilometer-deep shaft in the Xiangxi gold mine was investigated with real-time synchronized MTS 815 material testing machine and PCI-II AE instrument. The results show that the in situ stress changes from being dominated by horizontal stress to being dominated by vertical stress with depth. The horizontal maximum principal stress and vertical stress gradually increase with depth and reach a high-stress level (greater than 25 MPa) at a depth of 1000 m. The direction of the maximum principal stress is near the north. Meanwhile, to analyze the accuracy of the measured in situ stress comparatively, the stress relief measurements were performed at a depth of 655–958 m in the mine, using the Swedish LUT rock triaxial in situ stress measurement system. The distribution of deep in situ stress obtained by the stress relief method agrees well with that by the AE method, which proves the reliability of the AE in situ stress testing method based on the geological core ground reorientation technology.

In Situ Stress Measurement and Inversion in Deep Roadway

2013 ◽  
Vol 734-737 ◽  
pp. 759-763 ◽  
Author(s):  
Yong Li ◽  
Yun Yi Zhang ◽  
Ren Jie Gao ◽  
Shuai Tao Xie
Keyword(s):  
Field Measurement ◽  
Stress Measurement ◽  
Measurement Data ◽  
Back Analysis ◽  
In Situ Stress ◽  
Deep Mine ◽  
Accuracy Requirement ◽  
Initial Stress Field ◽  
In Situ Stress Measurement

Jixi mine area is one of the early mined areas in China and it's a typical deep mine. Because of large deformation of underground roadway and dynamic disasters occurred frequently in this mine, five measurement points of in-situ stress in this mine was measured and then analyzed with inversion. Based on these in-situ stress measurement data, numerical model of 3D in-situ stress back analysis was established. According to different stress fields, related analytical samples of neural network were given with FLAC program. Through the determination of hidden layers, hidden nodes and the setting of parameters, the network was optimized and trained. Then according to field measurement of in-situ stress, back analysis of initial stress field was conducted. Compared with field measurement, with accuracy requirement satisfied, it shows that the in-situ stress of rock mass obtained is basically reasonable. Meanwhile, it proves that the measurement of in-situ stress can provide deep mines with effective and rapid means, and also provide reliable data to optimization of deep roadway layout and supporting design.

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