Aiming at the shortcomings of BP neural network in practical applications, such as easy to fall into local extremum and slow convergence speed, we optimized initial weights thresholds using particle swarm optimization (PSO). Additionally, cloud computing service, web technology, database numerical simulation were integrated construct an intelligent feedback analysis program for underground engineering safety monitoring based on PSO-BP algorithm. The could conveniently, quickly, intelligently...

In the project focused on CO2-enhanced coalbed methane exploitation and geological storage, seam network structure of coal seams serves as a conduit for gas migration, diffusion, displacement, storage. The mechanical properties these are intrinsically linked to propagation evolution cracks. Prolonged exposure CO2 adsorption environments inevitably alters their properties. Consequently, experimental research has been conducted microstructure with potential storage in China. results indicate...

A reasonable evaluation of unloading deformation characteristics is great significance for the effective analysis and stability surrounding rocks after underground excavation. In this study, damage-controlled cyclic triaxial loading tests were conducted to investigate pore compaction mechanism its influences on behavior red sandstone, including Young's modulus, Poisson's ratio, volumetric strain, irreversible strain. The experimental results show that increases strains can be attributed...

Surrounding rock deformation and consequent support failure are the most prominent issues in red-bed tunnel engineering mainly caused by effects of unloading, rheology, swelling. This study investigated mechanical responses two kinds mudstone sandstone under unloading conditions via laboratory observation. Volume dilation was observed on rocks during dilatancy stress linear with initial confining pressure. However, ratios to peak kept at a range from 0.8 0.9, regardless pressures. Both...

The in situ stress distribution is one of the driving factors for design and construction underground engineering. Numerical analysis methods based on artificial neural networks are most common effective inversion. However, conventional algorithms often have some drawbacks, such as slow convergence, overfitting, local minimum problem, which will directly affect inversion results. An intelligent inverse method optimizing back-propagation (BP) network with particle swarm optimization algorithm...

Transversely isotropic rock is a typical anisotropic type. The existing creep constitutive models for do not fully reflect the mechanical properties of transversely rock. By considering set parameters as internal connection among specimens with different bedding directions, three-dimensional equation derived, which can effectively describe characteristics instantaneous strain, decaying creep, and steady A method to determine model proposed. Based on test experimental data horizontally...

The underground powerhouse of the Shuangjiangkou hydropower station is one largest caverns under construction in China, and its stability during crucial for safe construction. To study surrounding rock excavation, displacement stress were monitored by multi-point meters bolt meters. Based on monitoring data, elastic modulus, Poisson’s ratio, friction angle, cohesion inversely analyzed PSO-BP algorithm. Then, back-analyzed parameters used to simulate subsequent excavations predict following...

The concrete lining of high-pressure water conveyance tunnels permeates under water. Dense and hydrophobic coating can effectively improve the impermeability concrete. However, exhibits varying in different environments, which even lead to detachment or damage. objectives this study are by using a polymer coating, through experiments. This applied called SCU-SD-SP-II (SSS) surfaces, it formed composite protective layer with an epoxy-modified silicone (EMS) coating. A series tests were...

Landslides are usually caused by rainstorms and geological processes such as earthquakes may have a massive impact on human production life. The hazard chain of landslide–river blockage–outburst flood is the most common landslides. A database based existing landslide cases was established in this study to investigate assessment formulas risk river blockage, dam stability, peak discharge after has broken. model blockage–breaching established, including downstream vulnerability. case Baige...

Longwave radiation is an important open-air environmental factor that can significantly affect the temperature of concrete, but it has often been ignored in analysis concrete structures. In this article, improved analytical model was proposed by considering solar radiation, thermal convection, conduction and especially longwave radiation. Temperature monitoring block carried out to verify analyze heat energy characteristics concrete. As demonstrated experiment, under influence at top could...

For high cutting slopes, it is quite necessary to set pre-reinforced structures before the slope excavation avoid failure during excavating. In this paper, multi-wedge translation mechanism used analyze stability of slopes with piles. First, multivariate functions are established calculate safety factor for Based on excavating process, can be determined that whether need piles If need, most significant pile design stabilising force. Then expressions derived force provided by increase assure...

The discrimination of river blockages is very important for the risk assessment landslide disasters and secondary hazards. Experimental studies statistical analyses were carried out to explore formation process discriminant criteria caused by landslides. An adjustable slide chute was designed built conduct forty-five experiments. According experimental results, blockage identified as having six types based on differences between water depth height dam, degree increased from 70% 100% angle,...

The first part of this paper presents the major drawbacks traditional methods for generating joints in Particle Flow Code 2D (PFC2D). Violent oscillations postpeak shear stress and shear‐induced dilation normal direction occur specimens generated by directly removing bonds using discrete fracture network (DFN) method. additional wall method can be used to simulate realistic mechanical properties direct test, but it is difficult achieve a uniform initial distribution within specimen due...

This paper presents a case history detailing the two concentrating belts of unloading fractures found in right bank slope Dagangshan Hydropower Station, China. Based on analyses about potential sliding modes which controlled by fracture belts, cause three in-situ crack cases are discussed. The results numerical calculation illustrate stability excavation and rock mass failure trend, verify development patterns cracks instability mode hazard blocks, offer references for reinforcement. most...