High-resolution image transmission is required in safety helmet detection problems the construction industry, which makes it difficult for existing methods to achieve high-speed detection. To overcome this problem, a novel super-resolution (SR) reconstruction module designed improve resolution of images before module. In module, multichannel attention mechanism used breadth feature capture. Furthermore, CSP (Cross Stage Partial) YOLO (You Only Look Once) v5 presented reduce information loss...

In this paper, ordinary Portland cement, ultrafine polyurethane, and epoxy resin were selected as typical grouting materials. Grouting simulation tests first conducted to prepare the grouted concrete crack sample. The effect of parameters (i.e., aperture roughness), grout water–cement ratio, pressure on water-plugging performance different materials was explored through impermeability test. microstructure cracks analyzed by means scanning electron microscopy (SEM) computed tomography (CT),...

In order to study permeation grouting reinforcement effect in the sand layer, a set of test device is developed, which consists power device, pressure‐bearing slurry tank, and several frames. Compressive strength, deformation modulus, permeability coefficient are selected be evaluation index effect. Grouting under different water‐cement ratio cement curing time were measured. Eventually, laboratory conditions, fitting formulas have been obtained describe quantitative relationship between...

Water and mud inrush disaster is easily induced during tunnel construction through water-rich fault fracture zones. In this paper, based on the field data, process of water in tunnels introduced detail, generation conditions evolution mechanisms have been analyzed. Results show that key factors include poor strata lithology, abundant groundwater excavation disturbance. These provide material conditions, source power start-up for inrush, respectively. The can be divided into three stages:...

Subsection split grouting technology can effectively improve the efficiency and homogeneity of in a target reinforcement area. It is therefore necessary to clarify mechanism characteristics soft filling medium under condition grouting. A three-dimensional simulation test segmented was conducted. The distribution thicknesses veins were obtained mechanical reinforcement, based on different veins, revealed. After grouting, uniaxial compression an indoor permeation Based method region-weighted...

A bentonite slurry mixed with seawater is prone to sedimentation, which will reduce the quality of filter cake and lower stability excavation surface in undersea tunnels. It necessary study performance influencing factors seawater. This article simulates process shield tunnel construction, where pressurized penetrates into sand layer forms a when stops pressurizing. We investigated effects bentonite, additives (CMC), fine sand, pressure, formation permeability on cake. The sedimentation mud...

Due to the hidden nature of grouting project, it has not been possible get a clear picture slurry transport law, and most existing permeation theories have ignored tortuous characteristics pore channels porous media. Based on fractal theory media equation seepage motion viscous time-varying Bingham fluid, theoretical model with fluid is established, viscosity tests are carried out for C-S obtain slurry. A set simulation experiment device was designed, variation curve pressure time under...

A water-rich sand layer is a common stratum in marine underground engineering. Grouting technology for soil or rock sealing, method to solve the water seepage problem, and can be used geological challenges layers. grouting-reinforced body deteriorates by long-term erosion of seawater, resulting attenuation performance solid. Obtaining decay law guarantee safe operation structure over long life cycle. To this end, describing solid damage after seawater erosion, stress–strain curve...

Grouting is an effective method to reduce permeability and improve the mechanical performance of sand layers, preventing a disastrous inrush water. A scientific grouting design scheme premise for satisfying reinforcement requirements. Due lack theoretical basis current designs, projects are conducted empirically blindly. This paper presents quantitative in layers. Based on this method, realized judgment mode, determination range calculation effect. Moreover, fracture–compaction model...

The creep damage behavior of rocks is very important for evaluating the stability and safety key rock engineering. Based on Lianhua Tunnel Project in China, this paper aims to study mechanics, influencing factors constitutive models sandy shale. In order achieve these goals, a uniaxial compressive strength test under different moisture contents load levels were carried out. According results, parameters (elastic coefficients E1 E2 viscosity η1 η2) Burgers Model achieved, relationship between...

In order to realize the diffusion law of segmental grouting in muddy fault tunnel engineering, a three-dimensional simulation test has been done. Three times operation have done for three adjacent sections pipe. Grouting pressure, injection rate, soil pressure field, and seepage field real-time monitored stages. The effect on effective stress analyzed. Results show that previous can affect later operation. Due operation, grouted stratum be compacted will conquer greater resistance...

Contact curvature plays a pivotal role in the Young’s modulus determination and mechanical response of particle. This paper presents sensitivity analysis particle morphology to contact its influence on during elastic deformation X-ray computed micro-tomography (μCT) was conducted obtain prototype single The digital information scanned particle, including 2D slices 3D rendering processed variation examined using circular (spherical at 3D) polynomial fitting methods. sections are taken into...

Reinforced concrete is one of the most critical composite material in modern civil engineering and can improve tensile resistance cement-based concrete, its passivation film plays an important role durability preventing steel corrosion. But, due to size limitations, destruction micro-scale bars has not been well studied. In this work, reactive molecular dynamics simulation was employed studying mechanical properties film. The uniaxial stretching different compounds γ-FeOOH, γ-Fe2O3 Fe...

In fracture or compaction grouting projects of sand layer, there exist many compacted regions on both sides grout veins around bulbs. It has an important effect the final reinforcement layer that how much performance is improved after being compacted. Compression modulus, cohesion, and permeability coefficient are selected to be indexes sand. The relationship between properties pressure been tested analyzed. And influences clay content initial water ratio have studied. Results show can...

Water‐rich sand is a common stratum in marine underground engineering. Grouting the most method for solving geological disasters water‐rich sand. However, environment differs greatly from land environment. The erosion and seepage of seawater ion cause significant deterioration grouted body, which reduces physical mechanical properties body. maintenance body performance guarantee long‐term safe operation tunnel In order to solve problem long‐life grouting design layer environment, an...

Through the pre-grouting engineering practice of F1 fault fracture zone in People's Hall Station Qingdao Metro Line 4, research on Strengthening Technology shallow and large section metro tunnel through is carried out, effective means to control crossing are explored. The results show that it an method treat collapse by using combined grouting first detection grouting, combination surface tunnel. For near sea, order prevent continuous erosion seawater ions station structure, cement-water...