Study on Creep Constitutive Model of Stratified Siltstone and its Application to Environmental Hazards Treatment

2021 ◽  
Author(s):  
Yiran Yang ◽  
Xingping Lai ◽  
Tao Luo ◽  
Kekuo Yuan ◽  
Feiyong Wang
Keyword(s):  
Numerical Simulation ◽  
Constitutive Model ◽  
Ground Surface ◽  
Environmental Hazards ◽  
Surrounding Rock ◽  
Living Environment ◽  
Surface Settlement ◽  
Main Body ◽  
Ground Surface Settlement ◽  
Simulation Results

Abstract Mining causes environmental hazards which have an adverse effect on ecological system and human living environment. Rock is the main body of underground coal mining, and among them stratified siltstone is very common. Creep and instability of underground stratified siltstone is one of the main inducing factors of ground fissures and ground surface settlement. In this study, on the basis of fully considering its stratified structure features, we built and theoretically analyzed the viscoelastic-viscoplastic constitutive model of stratified siltstone. Creep tests and numerical simulation under multi-stress were conducted. Numerical simulation results under high, medium and low stress were consistent with the creep test results, it made up for the deficiency of traditional creep models in predicting plastic deformation at low stress level. Numerical simulation results showed that under different boundary conditions, the proposed model had advantage to more accurately simulate creep behavior of stratified siltstone compared with traditional models. Also, the numerical simulation results reveled creep characteristics of underground roadway surrounding rock, based on which a supporting scheme was put forward. In the stress adjustment stage, the strain rate dropped significantly from 14.6mm/d to 10.3mm/d. Then, it entered the deceleration creep stage. Creep of roadway surrounding rock and ground surface settlement stopped. The environmental hazards were solved to a great extent.

Prediction of Shield Tunnelling-Induced Ground Settlement Considering Soil-Water Coupled and around Soil Disturbance Damage

2010 ◽  
Vol 168-170 ◽  
pp. 357-364
Author(s):  
Ji Feng Liu ◽  
Bo Liu ◽  
Hui Zhi Zhang
Keyword(s):  
Numerical Simulation ◽  
Soil Water ◽  
Ground Surface ◽  
Soil Disturbance ◽  
Surface Settlement ◽  
Shield Tunnel ◽  
Tunnel Construction ◽  
Ground Settlement ◽  
Ground Surface Settlement ◽  
Shield Tunnelling

to evaluate the influence of soil-water coupled and shield tunnel construction induced around soil disturbance damage on ground surface settlement, the process of shield tunnel construction induced around soil disturbance is analyzed, the FLAC3D numerical simulation are carried out, and a newly-modified tunnelling-induced ground settlement calculation method based on disturbance degree of around soil and soil-water coupled is presented, and these methods are applied in case of Beijing Metro 10thLine. It is indicated that considering the influence of the shield tunnelling-induced around soil disturbance damage, and soil-water coupled induced soil properties weakening and the excess pore water pressure dissipating induced soil consolidation to the ground surface settlement are necessary, the calculating result of the newly-modified surface settlement prediction method, and the result FLAC3D numerical simulation all agree well with in-site observed data of Beijing Metro 10th Line.

Control Standard of Ground Surface Settlement Induced by Running Tunnel Construction in Beijing Subway

2011 ◽  
Vol 117-119 ◽  
pp. 721-725 ◽  
Author(s):  
Cheng Ping Zhang ◽  
Li Min Li ◽  
He Li ◽  
Jian Chen Wang
Keyword(s):  
Numerical Simulation ◽  
Ground Surface ◽  
Control Valve ◽  
Surface Settlement ◽  
Tunnel Construction ◽  
Ground Settlement ◽  
Simulation Based ◽  
Ground Surface Settlement ◽  
Subway Construction ◽  
Beijing Subway

Ground settlement, especially the ground surface settlement induced by subway tunneling is an important issue. However, there is no an agreed standard for controlling ground surface settlement during the subway construction at present. The control standard of ground surface settlement was studied using the methods of statistical analysis and numerical simulation based on the running tunnel in Beijing subway. According to the research results, a conclusion could be obtained that the ground surface settlement can be controlled within 40 mm using the general construction measures in Beijing subway running tunnel construction, and furthermore, the settlement of 40mm will not damage the existing nearby structures and utilities including neighboring buildings, bridges and pipelines, etc. So the control valve of 40 mm is rational, which can be adopted as the control standard of ground surface settlement induced by running tunnel construction in Beijing subway.

scholarly journals Characteristics of Stress Transfer and Progressive Fracture in Overlying Strata due to Mining-Induced Disturbances

2018 ◽  
Vol 2018 ◽  
pp. 1-13 ◽  
Author(s):  
Xiang-feng Lv ◽  
Hong-yuan Zhou ◽  
Ai-wen Wang ◽  
Chun Feng ◽  
Xiao-chun Xiao
Keyword(s):  
Numerical Simulation ◽  
Underground Mining ◽  
Ground Surface ◽  
Stress Transfer ◽  
Surface Settlement ◽  
Stress Concentrations ◽  
Tunnel Face ◽  
Working Face ◽  
Ground Surface Settlement ◽  
Overlying Strata

In this study, based on the mining of the 13210 working face in the Yima coal mine of the Gengcun village, China, a simplified mechanical model for the analysis of dynamic destabilization of the overlying strata during underground mining was constructed. The numerical simulation was used to analyze the stress patterns in the advanced abutments of the tunnel face and the characteristics of dynamic failures in the overlying strata. Furthermore, similitude experiments were conducted to study the process of stress release and deformation in the overlying strata, and to analyze the effects of overburden destabilization on the ground surface settlement. The theoretical analysis indicated that if the geometric parameters of a working face are fully determined, a stiffness ratio no greater than 1 is required for dynamic destabilization to occur. The numerical simulation results show that the stress in the overlying strata decreases with a decrease in distance from the tunnel face. The stresses in the advanced abutments initially increase with an increase in distance from the tunnel face, followed by a decrease in stress, and an eventual stabilization of the stress levels; this corresponds to the existence of a “stress build-up zone,” “stress reduction zone,” and “native rock stress zone.” In similitude experiments, it was observed that a “pseudoplastic beam” state arises after the local stresses of the overlying strata have been completely released, and the “trapezoidal” fractures begin to form at stress concentrations. If the excavation of the working face continues to progress, the area of collapse expands upward, thereby increasing the areas of the fracture and densification zones. Owing to the nonuniform settlement of the overlying strata and the continuous development of bed-separating cracks, secondary fractures will be generated on both sides of the working face, which increase the severity of the ground surface settlement.

scholarly journals Development and Application of Model Test System for Reconstruction and Expansion of Existing Shallow Single-Hole Tunnel into Twin-Arch Tunnel

2021 ◽  
Vol 2021 ◽  
pp. 1-17
Author(s):  
Yanling Jia ◽  
Aohui Ouyang ◽  
Siyu Wang ◽  
Xing Liang ◽  
Bin Wang ◽  
...  
Keyword(s):  
Model Test ◽  
Ground Surface ◽  
Test System ◽  
Surrounding Rock ◽  
Surface Settlement ◽  
Laboratory Model ◽  
Internal Stresses ◽  
Tunnel Excavation ◽  
Single Hole ◽  
Ground Surface Settlement

In this study, we developed a tunnel excavation model test system to investigate the deformation and mechanical response of the surrounding rocks and tunnel structure during the reconstruction and expansion of an existing shallow single-hole tunnel into a twin-arch tunnel. A model test was conducted to study the variation in the ground surface settlement characteristics, surrounding rock pressure, and internal stresses of the supporting structure and midwall during the construction process. The influence of the excavation distance on displacements and structural stress between the faces of the left and right tunnels was analysed using numerical software. A comparison between the model test results and the monitoring and measurement construction results revealed a fairly consistent ground surface settlement, indicating that the system is stable and reliable and can be widely applied to laboratory model test research on tunnel excavation. Results show that the excavation of the first tunnel had a significant effect on the stability of the surrounding rock within the distance of a single-tunnel span behind the tunnel face. When the excavation distance between the two tunnels exceeded twice the length of the single-tunnel span, its effect on the stresses and deformation of the reconstructed twin-arch tunnel was negligible.

Numerical Analysis of Construction Method in Shallow-Buried Large-Section Loess Tunnel

2014 ◽  
Vol 580-583 ◽  
pp. 997-1000 ◽  
Author(s):  
Zhi Jie Sun
Keyword(s):  
Numerical Simulation ◽  
Numerical Analysis ◽  
Ground Surface ◽  
Construction Method ◽  
Surrounding Rock ◽  
3D Numerical Simulation ◽  
Large Section ◽  
Research Results ◽  
Construction Methods ◽  
Ground Surface Settlement

To research the deformation regularity of large section loess tunnel in construction procession with different construction methods, 3D Numerical Simulation is applied and the large-section loess tunnel of highway is taken as an example. Comparing deformation regularity of surrounding rock in three types of construction method conditions, the research results show that:The CRD method takes precedence in the condition of the convergence of surrounding rock is large. The both sides heading method takes precedence in the condition of ground surface settlement is large.

3D Numerical Simulation Analysis and Pre-Estimation New Technology of Ground Collapse Caused by Subway Shield Construction

2013 ◽  
Vol 405-408 ◽  
pp. 1239-1246
Author(s):  
Yuan Liang Liu
Keyword(s):  
Numerical Simulation ◽  
Simulation Analysis ◽  
New Technology ◽  
Technical Problem ◽  
Ground Surface ◽  
Simulation Software ◽  
Surface Settlement ◽  
3D Numerical Simulation ◽  
Ground Collapse ◽  
Ground Surface Settlement

The prediction of ground collapse caused by subway shield construction has been an important technical problem in urban subway shield construction, if the ground collapse could be pre-estimated, it could be able to take appropriate precautionary measures in advance to avoid the occurrence of ground surface settlement before the project construction, but it’s difficult to predict and calculate the settlement accurately. This paper analyzed main causes of ground collapse caused by shield construction, summarized the influence of several important parameters to surface settlement and then Midas GTS 3D numerical simulation software was used to simulate shield construction process and calculate ground surface settlement, to calculate stress, strain and displacement of overlying strata above the shield driving machine, obtained calculated values of surface settlement to predict ground collapse. Practice has proved that this pre-estimation new technology is in accordance with fact, it provides a useful reference for subway shield construction project.

Contrast Analysis on Deformation Characteristic of Urban Subway Tunnel Excavation by Numerical Simulation and Field Measurement

2012 ◽  
Vol 170-173 ◽  
pp. 1704-1707
Author(s):  
Wei Feng Yang ◽  
Xi Liu ◽  
Yi Wang ◽  
Ming Li
Keyword(s):  
Numerical Simulation ◽  
Field Measurement ◽  
Ground Surface ◽  
Horizontal Displacement ◽  
Surface Settlement ◽  
Loss Ratio ◽  
Tunnel Excavation ◽  
Geological Conditions ◽  
Ground Surface Settlement ◽  
Ground Loss

Under the particular geological conditions of clay and sandy soil interbed, through numerical analysis and field monitoring, the surface settlement, horizontal deformation and the stress distribution were analyzed after the tunnel excavation in a metro station in Beijing, China. There are differences of surface deformation whether the backfill grouting behind arch during tunnel excavation. While the backfill grouting behind arch, the ground surface settlement and the horizontal displacement reach 9.36 mm and 2.16 mm respectively. But while no backfill grouting behind arch, the ground surface settlement and the horizontal displacement are 14.51 mm and 8.85 mm respectively. The maximum ground settlement induced by tunnel excavation is directly proportional to ground loss ratio. When the ground loss ratio is 1%, the result is well consistent with the field measurement value and the numerical simulation result.

scholarly journals Study on adaptability of primary support arch cover method for large-span embedded tunnels in the upper-soft lower-hard stratum

2019 ◽  
Vol 11 (1) ◽  
pp. 168781401882537 ◽  
Author(s):  
Junbao Wang ◽  
Qi Huo ◽  
Zhanping Song ◽  
Yuwei Zhang
Keyword(s):  
Numerical Simulation ◽  
Plastic Zone ◽  
Surrounding Rock ◽  
Surface Settlement ◽  
Supporting Structure ◽  
Provincial Hospital ◽  
Excavation Process ◽  
Simulation Results ◽  
Final Settlement ◽  
Primary Support

The Provincial Hospital Station of Guiyang Metro Line No. 2 in China is located on the upper-soft lower-hard stratum. In order to analyze the adaptability of primary support arch cover method for the project, the construction process of the main tunnel of the Provincial Hospital Station is simulated by virtue of numerical simulation. Meanwhile, the excavation process of the tunnel is simulated by the double-side drift method for comparison. The numerical simulation results show that the primary support arch cover method has advantages in settlement control, plastic zone distribution, and supporting structure safety. Only the primary supporting structure is relatively weak in the rock–soil interface and on the arch shoulders and vault, and liable to tension failure. However, the application of strengthened primary support can significantly improve this unfavorable situation. Therefore, it is suggested that the primary support arch cover method be adopted for the construction of the main tunnel of the Provincial Hospital Station. The numerical simulation results obtained by primary support arch cover method are consistent with the field data in terms of the change trend of surface settlement, and the final settlement value is also similar. On this basis, the influence of grade variation of underlying surrounding rock on surface settlement and surrounding rock plastic zone distribution caused by the two methods is further simulated, and the grade range of underlying surrounding rock suitable for primary support arch cover method is given in the article.

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