This paper is based on the construction of underground Pile-Beam-Arch station at Beitaipingzhuang Station Beijing Metro Line 12. It employs finite element software for three-dimensional numerical modeling, faithfully reproducing entire process. The results indicate that excavation pilot tunnel and stage secondary lining buckle arch are main causes surface deformation. Additionally, primary factor inducing deformation in middle column side pile. On this basis, investigates influence four...

To analyse the influence of normal stress (σn) and steel tube strength on an anchor cable with a C-shaped (ACC), we selected Q235 tubes Q345 as representative ACCs carried out double shear tests ACC-reinforced jointed rock masses. Based test results, ACC axial force under different stresses, characteristics force-shear displacement curve anchored flat structural plane (FSP) in mass, failure mode contribution to concrete surface were studied. The results show that 2 ~ 10 MPa σn, angle varies...

Abstract To analyze the plastic failure process and mechanism of gob floor in close‐distance coal seams mining, a simplified mechanical model lateral abutment pressure was proposed to derive stress surrounding rock. The distribution characteristics deviator were obtained, effect geological parameters (coal depth H horizontal coefficient λ ) studied. By combining Mohr–Coulomb theory, influence rock cohesion c , internal friction angle φ different seam depths coefficients on zone obtained....

Deformation control of deep roadways is a major challenge for mine safety production. Taking roadway with burial depth 965 m in North China as the engineering background, on-site investigation found that significant creep deformation occurred surrounding rock roadway. The original supporting U-shaped steel support failed due to insufficient strength. mass near experienced transition from triaxial stress conditions biaxial and even uniaxial states result excavation unloading, leading gradient...

Based on specific examples of underpass tunnel blasting, field measurements, and numerical simulation studies are carried out. According to the results blasting vibration data measured on-site, a regression model velocity is established. wavelet packet energy spectrum analysis method, effect frequency response intensity studied. In addition, maximum charge per delay allowed for obtained by formula inversion. Relying ANSYS/LS-DYNA establish three-dimensional model, accuracy can be checked...

The gradual development of coal mining in deep areas has brought new challenges to the surrounding rock support system. It is imperative design elements that exhibit strong tensile and shear resistance are suitable for pretension load. In this paper, an anchor cable bolt with a c-shaped tube (ACC) proposed, order study performance ACC, mechanical properties ACC ordinary bolts various diameters loads tested. addition, comparative analysis performed investigate effect diameter load on strength...

Aiming at the measured vibration signals collected during tunnel blasting construction, a noise reduction method based on overall average empirical mode decomposition (CEEMDAN decomposition) combined with wavelet packet analysis was in troduced. First, series of multiple intrinsic modal components were obtained by CEEMDAN decomposition, and containing selected using correlation coefficients, checked spectrogram variance contribution rate components. Then, threshold used to process noise....

Compressing Transformer inputs into compressd tokens allows running LLMs with improved speed and cost efficiency. Based on the compression method ICAE, we carefully examine position identifier choices for compressed also propose a new loss. We demonstrate empirically that our proposed methods achieve significantly higher ratios (15x compared to 4x ICAE), while being able attain comparable reconstruction performance.

Numerous recent works target to extend effective context length for language models and various methods, tasks benchmarks exist measure model's memorization length. However, through thorough investigations, we find limitations currently existing evaluations on capability. We provide an extensive survey in this work propose a new method called forgetting curve the capability of long-context models. show that has advantage being robust tested corpus experimental settings, not relying prompts...

The shallowly buried covered excavation PBA method is one of the new construction methods that has attracted widespread attention in past 20 years. Understanding deformation strata and supporting structures key to ensuring safe stations at present. Relying on Beijing Line 12 Beitaipingzhuang subway station based 1:40 model test, production similar materials for plan are introduced. According actual process station, two pile foundation strip more realistic. variations around structure during...

The PBA construction method is suitable for urban subway in situations with dense traffic and many surrounding buildings can effectively reduce surface disturbance control subsidence. Based on field-measured data, this study creates numerical finite element models of 3D stratum-structure, studies the influence each process conversion subsidence ground force station supporting structure during station, clarifies optimal parameters. research results show that consistency between field...

Steel pipe columns are an important component in subway station construction and with stand stress state internal force during the process. Based on engineering background of Beijing subway, this paper introduces geological conditions, structure types, monitoring steel 10 stations constructed by PBA method. The field indicates that greatest change column occurs stage 1 (beam, primary support, secondary lining buckle arch stage), no matter pile foundation or strip station, which accounts for...

Abstract Aiming at the considerable deformation of surrounding rock and difficulty supporting a roadway affected by mining close-distance coal seams, this paper takes 10607 gas extraction Malan Coal Mine as subject study, an analysis stress distribution is conducted using circular hole problem involving plane strains. Using mechanical model roadway, formula for second invariant J 2 deviatoric theoretically derived. The characteristics pillar floor longwall panel are analyzed simulation...