Abstract: A dual-direction synchronous loading method for a true-triaxial test apparatus includes the following steps: Step S1, loading a sample and adjusting the sample at a center of a sample box and a rigid loading frame; Step S2, setting parameters and sending action instructions through a computer control panel; and Step S3, collecting load signals collected by each sensor acquired by a PID controller, and coordinating a size of triaxial dual-direction loading loads to realize a single instruction dual-direction synchronous loading. The method ensures that a rock sample is kept at a center of a pressure chamber before being loaded, so that a focus of a loading axis is always at a same position as a center of the sample in space, and the function of synchronous loading of two loading actuators in the same direction under a single instruction can be achieved.

Abstract: Provided are a long-term monitoring apparatus and method for surrounding rock fracture evolution process triggered by multiple-source dynamic disturbances. The apparatus includes a machine body framework, a borehole wall surrounding rock image acquisition module, a borehole wall multiple-source vibration monitoring module, an in-borehole walking module, and a monitoring signal storage and transmission module. The borehole wall surrounding rock image acquisition module, the borehole wall multiple-source vibration monitoring module, the in-borehole walking module, and the monitoring signal storage and transmission module are sequentially arranged on the machine body framework from front to back. The monitoring signal storage and transmission module is connected in a communicative manner to a computer outside a borehole. The present invention can achieve integrated monitoring of imaging and vibration within a borehole.

Abstract: Provided are a long-term monitoring apparatus and method for surrounding rock fracture evolution process triggered by multiple-source dynamic disturbances. The apparatus includes a machine body framework, a borehole wall surrounding rock image acquisition module, a borehole wall multiple-source vibration monitoring module, an in-borehole walking module, and a monitoring signal storage and transmission module. The borehole wall surrounding rock image acquisition module, the borehole wall multiple-source vibration monitoring module, the in-borehole walking module, and the monitoring signal storage and transmission module are sequentially arranged on the machine body framework from front to back. The monitoring signal storage and transmission module is connected in a communicative manner to a computer outside a borehole. The present invention can achieve integrated monitoring of imaging and vibration within a borehole.

Abstract: Provided is a method for judging geology of a time-delayed extremely intense rockburst as to deep tunnel engineering. Information about geological structures is recorded according to methods such as geological mapping and advanced geological prediction of the tunnel face. Geometric characteristics of burst craters formed during the rockburst are recorded by utilizing advanced geological drilling and profile scanning technologies in a rockburst-damaged zone. 3D geostress in the rockburst-damaged zone is measured by using a stress relief method or a hydraulic fracturing method to determine the orientation of the maximum principal stress. A 3D numerical calculation model is established based on initial geostress testing results and physical and mechanical parameters of rock and structural discontinuities obtained through on-site geological investigations.

Abstract: A true triaxial time-dependent dynamic disturbance test device for a deep-buried hard rock includes a rigid static load loading assembly and a rigid dynamic load loading assembly. The rigid static load loading assembly applies a static load to a rock test sample, and the rigid dynamic load loading assembly applies a disturbance stress to the rock test sample. Coupled application and control of a long time-dependent static force and a disturbance stress of the rock in a true triaxial disturbance stress state are achieved. The rigid dynamic load is provided with a disturbance rod in a loading direction, and a “point” disturbance mode is converted into a “face” disturbance mode through the disturbance rod, a disturbance hole and a test sample clamp, so that a disturbance mode more suitable for an actual working condition on site is provided while power consumption is reduced and time-dependent dynamic disturbance is achieved.

Abstract: A quantitative energy-absorption prevention and control design method includes: establishing a numerical calculation model, and performing a simulation calculation on excavation; determining a location and a range of rock-burst damage and a depth of a burst pit and providing an energy release amount at different positions; determining a location, a direction, and a dip angle of a structural plane; determining a design length of a free section of anchor rods, and in combination with a design anchoring force of the anchor rods, determining an optimal length of a single anchor rods; calculating ejection kinetic energy of rock blocks; and determining a length of an anchoring section of the anchor rod, a total length of the anchor rods, and a number of the anchor rods, such that a total energy absorbing capacity of all anchor rods is greater than the ejection kinetic energy at a time of the rock burst.

Abstract: A dual-direction synchronous loading method for a true-triaxial test apparatus includes the following steps: Step S1, loading a sample and adjusting the sample at a center of a sample box and a rigid loading frame; Step S2, setting parameters and sending action instructions through a computer control panel; and Step S3, collecting load signals collected by each sensor acquired by a PID controller, and coordinating a size of triaxial dual-direction loading loads to realize a single instruction dual-direction synchronous loading. The method ensures that a rock sample is kept at a center of a pressure chamber before being loaded, so that a focus of a loading axis is always at a same position as a center of the sample in space, and the function of synchronous loading of two loading actuators in the same direction under a single instruction can be achieved.

Abstract: The invention provides a method and system for a blast-induced vibration monitoring of a tunnel in high asymmetric in-situ stresses. According to the method, triaxial vibration sensors are respectively fixed in areas having different radial depths inside surrounding rocks of a stress concentration area behind a tunnel face of the tunnel in high asymmetric in-situ stresses, and each triaxial vibration sensor monitors blast vibration velocity and acceleration at a position thereof. The system comprises a plurality of triaxial vibration sensors which are fixed in areas having different radial depths inside surrounding rocks of a stress concentration area behind a tunnel face of the tunnel in high asymmetric in-situ stresses, and each triaxial vibration sensor is used for monitoring blast vibration velocity and acceleration at a position thereof. The method and system can improve the safety and the efficiency of tunnel excavation construction.

Abstract: The invention provides a method and system for a blast-induced vibration monitoring of a tunnel in high asymmetric in-situ stresses. According to the method, triaxial vibration sensors are respectively fixed in areas having different radial depths inside surrounding rocks of a stress concentration area behind a tunnel face of the tunnel in high asymmetric in-situ stresses, and each triaxial vibration sensor monitors blast vibration velocity and acceleration at a position thereof. The system comprises a plurality of triaxial vibration sensors which are fixed in areas having different radial depths inside surrounding rocks of a stress concentration area behind a tunnel face of the tunnel in high asymmetric in-situ stresses, and each triaxial vibration sensor is used for monitoring blast vibration velocity and acceleration at a position thereof. The method and system can improve the safety and the efficiency of tunnel excavation construction.

Abstract: Provided is a clamp of elastic box of stiff true-triaxial testing system and a displacement monitoring method for cuboid specimens. The clamp includes six pressing plates and eight plate springs, which form an elastic pressure box. One surface of the elastic pressure box can be disassembled, which simplifies the steps of rock sample mounting, and saving the mounting time. The springs connected with the pressing plates ensures the stability of the clamp but cannot affect the stress state of other surfaces of the rock sample during the test of the rock sample, thereby ensuring test accuracy. The invention further provides a displacement monitoring method for the rock sample by using the elastic box clamp. Six displacement sensors are mounted on the elastic box clamp, and the displacement of the rock sample can be monitored in real time.