To explore the influence of water inflow on safe and efficient tunneling construction TBM in water-rich Luohe Formation sandstone. Based data at main inclined shaft site Kekegai Coal Mine, a relationship model between speed is established by using statistical analysis machine learning theory; XRD SEM tests microstructural components sandstone are carried out to analyze mechanism argillaceous cemented affecting TBM. The Libsvm support vector (SVR) more effective than multiple regression...

To investigate the dynamic mechanical behavior and energy dissipation characteristics of low-temperature rock samples under cyclic impact loading, a temperature-controlled system that combines Hopkins bars with compensation device was used. Five temperature gradients were confirmed via trial test, tests conducted two kinds air pressures. The macroscopic damage at different temperatures, stress-strain curves, changes in peak stress strain, dissipation, cumulative microscopic structural after...

The penetration paths of grouts in sand layers are tortuous, and there is no reasonable grouting theory at present. By employing tortuous circular tubes as the internal pore channels layer, cylindrical diffusion model established for sand-layer grouting. First, permeability porous media average velocity Bingham slurry were deduced by considering tortuosity. Second, based on continuity equation, active steady-state differential equation pressure distribution function region obtained. Finally,...

Shield tunneling is widely used in urban subway tunnel construction. Old underground pipelines generally have small leakages that are difficult to find. The water leakage significantly reduces the stability of stratum, posing a threat safety shield Therefore, this study established 2D and 3D calculation models for analyzing law diffusion ground under pressure, influences pipeline range length on changes settlement during tunneling. model results show seepage mainly diffuses vertically...

Abstract To elucidate the distribution law of multiphase coupling slag discharge flow field in gas-lift reverse circulation during drilling shaft sinking, a numerical analysis model gas–liquid–solid was established by CFD–DEM (Coupling computational fluid dynamics and discrete element method) method, taking North Wind well Taohutu Coal Mine as an example. This presented pipe at bottom hole, validated through experimentation theoretical analysis. Finally, impact factors, including bit...

Artificial ground freezing has been widely practiced in construction of metro cross passage soft ground. The process creats a frozen mass improved compressive strength and impermeability, which will make the safely stand by itself at point excavation prevent cave-ins from happening. With this technique, freeze pipes are arranged like stretchers half opened umbrella two ends passage. Usually finite element analysis on transient temperature field soil can simulate propagation wall (frozen...

Taking into account moisture migration and heat change during the soil freezing process, as well influence of absolute porosity reduction on seepage we construct a numerical model hydrothermal coupling using laws conservation energy mass. The is verified by results large-scale laboratory tests. By applying calculation to formation artificial shaft temperature fields under action large-flow groundwater, conclude that groundwater with flow rates less than 5 m/d will not have significant impact...

Tunnel Boring Machines (TBMs) are a cutting-edge excavating equipment, but barely applied in underground coal mines. For TBM excavation projects involving the Zhangji mine, surrounding rock properties, stress field, cross section geometry, as well excavation-induced path of TBM-excavated mine roadways different from those traditional tunnels or roadways. Consequently, roadway supporting technologies and experiences cannot be relied on for this project. In order to research an appropriate...

Aiming at the complicated engineering conditions of auxiliary shaft repair in Banji coal mine, it was proposed to seal water around lining by differential control freezing technology using double rows holes. The outer row holes is completely frozen, and inner local frozen according degree destruction lining. pipe successfully developed requirements. Numeral simulations were used predict development temperature field; results showed that inward expansion range wall formed effectively limited...

In view of the fact that theory fracture grouting in deeply buried rock strata seriously lags behind engineering practices, a circular fracturing diffusion model single was established by considering numerous influencing factors strata, such as crustal stress characteristics, mechanical properties, and time‐varying characteristics serous viscosity. By setting intensity factor K I equal to material toughness IC at tip criterion for fracturing, equation derived verified experimentally....

The coupling effect of a slurry and the fractured rock layer controls spatial attenuation fracture channel width grouting pressure from hole to top diffusion. This paper comprehensively considers influencing factors such as mechanical properties injected mass time-varying characteristics serous viscosity introduces control equation establish single-fracture nonslab fracturing model. Combining motion law with extension form fracture, diffusion motion, considering geometry viscosity, is...

To investigate the mechanical properties of frozen saline soil, deep calcareous clay in Huanghuai mining area was chosen as research object, and an orthogonal test carried out to study true triaxial under influence multiple factors. The stress–strain characteristics, strength, trend salted with different salt content, stress paths, water relationships among above-mentioned factors, were investigated. analysis results by revealed order importance factors that influenced strength. primary...