Geological dynamic hazards during coal mining can be caused by the structural instability of a composite system roof rock and layers, joints in play vital role this instability. In paper, uniaxial compression simulation tests on rock–coal combined bodies with single joint at different angles were conducted using PFC2D software. particular, effects angle compressive strength (UCS), acoustic emission (AE) failure characteristics body analysed. The results show following. (1) causes decrease...

In deep mining, the lateral deformation of strip coal pillar appears to be a new characteristic. order study coal-mass, monitoring method and instrument were designed investigate in Tangkou Coalmine with mining depth over 1000 m. Because without influence repeated bedding sandstone roof is easy break angle between maximum horizontal stress roadway small, only about 287 mm lower than other pillars same coalmine. energy accumulation release cause discontinuous damage heterogeneous shows...

With regard to deep mining in metal mines, an investigation into the failure mode of fractured rock masses and their corresponding acoustic emission signal characteristics is conducted via uniaxial compression tests. Subsequently, a fractal damage renormalization group mechanical model developed explain behavior those masses. Employing bonded block (BBM) numerical simulation method, fracture process synthetic samples analyzed, thereby validating efficacy model. The simulations highlight...

The strength and failure characteristics for granite specimen with a set of cross‐joints different lengths were studied using PFC 2D software. results show that when the included angle α between main joint loading direction is 30° or 45°, no matter what β secondary joints is, controls crack propagation specimen, which occurs shear propagating from tips, corresponding uniaxial compressive low. Meanwhile, key at 0° 90° except 90°. tips. And, crossing upper tips found Their strengths are large....

Excavation in engineering significantly changes the initial stress state of rock, which makes rock inevitably complex unloading conditions, thus it is great significance to make a profound investigate mechanical characteristics under condition. This paper carried out two different paths including conventional triaxial compression and confining pressure tests on granite specimen from Sanshandao gold mine, systematically analyzed strength characteristics, deformation energy evolution laws....

Abstract In the realm of underground mining engineering, an investigation into failure mode deep fractured rock masses and their corresponding acoustic emission signal characteristics is conducted via uniaxial compression tests. Subsequently, a fractal damage renormalization group mechanical model formulated to elucidate behavior such masses. Employing BBM numerical simulation method, fracture process synthetic samples analyzed, thereby confirming efficacy aforementioned model. The...

A series of true triaxial compression (TTC) tests was conducted on granite specimens to investigate their fracture behavior. The sampled from a 1500‐m‐deep exploration borehole located the Sanshandao gold field in Shandong Province, China, where 1915‐m deep vertical shaft planned. Under stress, specimen shows anisotropic characteristics, which is manifested as different strains three directions specimen, and macroscopic fractures formed are parallel direction maximum principal stress σ 1...

In order to study the present state of tectonic stress field in northwest Jiaodong Peninsula, characteristics ground distribution along depth were analyzed with method regression analysis. A total 164 items situ measurement data collected. There are mainly two types states, one is σ H> h> v and other > >σ h , type related depth. The principal stresses H increase approximately linearly depth, gradients 0.0556, 0.0248, 0.0346, respectively. lateral pressure coefficients K H, h, av...

In deep hard‐rock mines, the failure of subsurface structures (e.g., tunnels, stopes, and shafts) has been a significant problem affecting mining safety due to high‐stress environment. this paper, mechanism structural instability is discussed, optimized excavation methods are proposed for stress control in gold mines. Based on field observation investigation joints distribution rock modes at 800–1200 m depth several large mines typical ultradeep borehole (2017 depth) northwest Jiaodong...

With the increase in mining depth, risk of ground pressure disasters yellow gold mines is becoming more and serious. This paper carries out a borehole test for behavior non-coal area with depth than 800 m Jiaodong area. The results show that under 1050 m, vertical principal stress same as minimum horizontal stress, which about 3 MPa per 100 m. When increases to 1350 by 3% self-weight maximum maintain steady growth rate In addition, based on results, operation monitoring system each mine...

In order to solve the problem that broken rock mass is easy collapse and fall during excavation of a submarine gold mine, two kinds bolt-mesh-concreting combined support schemes are designed by means field engineering geological investigation, indoor mechanics test, quality classification, theoretical analysis. We use numerical simulation for verification carry out industrial test. The results show stability grade surrounding III–IV; both can effectively control deformation failure rock....

Abstract Taking the auxiliary shaft proposed by Ruihai Mining Co., Ltd. as research object, in order to study load law of lining and ingate under high stress fluid solid coupling deep bedrock influence different permeability coefficient on stability surrounding rock, Midas software was used for numerical simulation analysis, results show that:( 1) After excavation, pore water pressure rock around wall decreases gradually, which is main permeable area. support, obviously raised, isolation...

Abstract In constructing hard rock mine deep shafts, the failure caused by high stress is a significant problem. A construction section extending from -930 m to -1271 level of 1527 shaft was selected as case study. Q, RMR, and GSI mass quality classifications surrounding were obtained determine shaft’s maximum unsupported sinking cycle height in different sections. The potential mode, zone shape, depth under then analyzed theoretically, empirically, numerical simulation, sequential control...