Study on soft rock strata movement with catastrophe theory

2008 ◽  
pp. 903-908
Keyword(s):  
Catastrophe Theory ◽  
Soft Rock ◽  
Strata Movement ◽  
Rock Strata

Judgement Method for Surrounding Rock Stability of Guanjiao Tunnel Based on Catastrophe Theory

2011 ◽  
Vol 90-93 ◽  
pp. 2307-2312 ◽  
Author(s):  
Wen Jiang Li ◽  
Su Min Zhang ◽  
Xian Min Han
Keyword(s):  
Plastic Strain ◽  
Catastrophe Theory ◽  
Soft Rock ◽  
Surrounding Rock ◽  
In Situ Monitoring ◽  
Engineering Practice ◽  
Stability Of Surrounding Rock ◽  
The Stability ◽  
Rock Tunnel

The stability judgement of surrounding rock is one of the key jobs in tunnel engineering. Taking the Erlongdong fault bundle section of Guanjiao Tunnel as the background, the stability of surrounding rock during construction of soft rock tunnel was discussed preliminarily. Based on plastic strain catastrophe theory, and combining numerical results and in-situ data, the limit displacements for stability of surrounding rock were analyzed and obtained corresponding to the in-situ monitoring technology. It shows that the limit displacements obtained corresponds to engineering practice primarily. The plastic strain catastrophe theory under unloading condition provides new thought for ground stability of deep soft rock tunnel and can be good guidance and valuable reference to construction decision making and deformation managing of similar tunnels.

scholarly journals A Comprehensive Review of the Mechanical Behavior of Suspension Bridge Tunnel-Type Anchorage

2019 ◽  
Vol 2019 ◽  
pp. 1-19 ◽  
Author(s):  
Yafeng Han ◽  
Xinrong Liu ◽  
Ning Wei ◽  
Dongliang Li ◽  
Zhiyun Deng ◽  
...  
Keyword(s):  
Mechanical Behavior ◽  
Failure Modes ◽  
Load Transfer ◽  
Mechanical Response ◽  
Soft Rock ◽  
Suspension Bridge ◽  
Development Trend ◽  
Factors Affecting ◽  
Research Results ◽  
Rock Strata

The recent surge of interest towards the mechanical response of rock mass produced by tunnel-type anchorage (TTA) has generated a handful of theories and an array of empirical explorations on the topic. However, none of these have attempted to arrange the existing achievements in a systematic way. The present work puts forward an integrative framework laid out over three levels of explanation and practical approach, mechanical behavior, and calculation method of the ultimate pullout force to compare and integrate the existing findings in a meaningful way. First, it reviews the application of TTA in China and analyzes its future development trend. Then, it summarizes the research results of TTA in terms of load transfer characteristics, deformation characteristics, failure modes, and calculation of ultimate uplift resistance. Finally, it introduces four field model tests in soft rock (mainly mudstone formations), and some research results are obtained. Furthermore, it compares the mechanical behavior of TTA in hard rock strata and soft rock strata, highlighting the main factors affecting the stability of TTA in soft rock formation. This paper proposes a series of focused topics for future investigation that would allow deconstruction of the drivers and constraints of the development of TTA.

Analysis on the Mechanical Behavior of Pipe Roof and Rock Bolt of Shallow and Unsymmetrical Tunnel in Soft Rock

2012 ◽  
Vol 443-444 ◽  
pp. 267-271
Author(s):  
Xu Dong Cheng ◽  
Peng Ju Qin
Keyword(s):  
Soft Rock ◽  
Surrounding Rock ◽  
Mechanical Behaviors ◽  
Maximum Displacement ◽  
Tunnel Excavation ◽  
Finite Element Software ◽  
Highway Tunnel ◽  
Geological Conditions ◽  
The Impact ◽  
Rock Strata

In this paper, the mechanical behaviors of pipe roof and bolt of shallow and unsymmetrical tunnel in soft rock are analyzed. Through the finite element software Phase2.0, combined with the geological conditions that construction site often appear, the mechanical behaviors of pipe roof and bolt and surrounding rock in the process of horseshoe highway tunnel construction in the condition that surface is soft rock and underground for the bedrock are analyzed. Research results show that: after tunnel excavation in soft rock, surrounding rock near the tunnel is easy to suffer soft-rock large deformation even failure, which needs to timely support；Due to the impact of the unsymmetrical tunnel, the mechanical behaviors of surrounding rock are unsymmetrical, such as the maximum displacement of tunnel around 0.4 m distant from apex of arch ring, the stress is asymmetrical on both sides of the tunnel arch ring etc; In addition, pipe roof can effectively prevent from the displacement of soft rock strata, improve tunnel strength factor, reduce the plastic zone of surrounding rock. This paper provides theoretical basis for the design of pipe roof and bolt.

Simulation Analysis of the Soft Rock Inclined Shaft Surrounding Rock Control with Different Bolt Support Patterns

2014 ◽  
Vol 988 ◽  
pp. 377-382 ◽  
Author(s):  
Peng Fei Jiang
Keyword(s):  
Compressive Stress ◽  
Simulation Analysis ◽  
Soft Rock ◽  
High Strength ◽  
Surrounding Rock ◽  
Tension Stress ◽  
Deformation And Failure ◽  
Stress And Deformation ◽  
Rock Strata ◽  
Bolt Support

Taking +150 inclined shaft going through the soft rock strata at Muchengjian mine as the background, and based on the analysis of the deformation and failure feature of the roadway surrounding rock in the soft rock strata, this paper makes X-Ray Differaction (XRD) phase analysis of the soft rock; using finite difference numerical software FLAC3D, it stimulates and makes comparative analysis of the stress and deformation distribution characteristics of the roadway surrounding rock with bolt support with different intervals, and the support of the high-strength bolt with high pre-tension stress in the inclined shaft through the soft rock strata. The results show that the roadway surrounding rock in the +150 inclined shaft at Muchengjian mine is swelling soft rock prone to softening, degradation and swelling in water, which is bad for the roadway support; different types of rock strata have significant different impact on the stress and deformation of the roadway surrounding rock; for the soft rock roadway, the increased pre-tension stress of the bolt can cause higher compressive stress in the roadway surrounding rock and reduce the tension failure of the surrounding rock;compared with the end anchorage, the full-size anchorage with high pre-tension stress can cause the overlap of the conical compressive stress zone and enhance the roadway overall support.

Research of Safe Distance between Concealed Karst Cave and Tunnel

2013 ◽  
Vol 405-408 ◽  
pp. 1283-1287
Author(s):  
Yong Biao Lai ◽  
Chun Sheng Qiao ◽  
Chen Guang Bai
Keyword(s):  
Catastrophe Theory ◽  
Total Potential Energy ◽  
Karst Cave ◽  
Safe Distance ◽  
Rock Stratum ◽  
Distance Calculation ◽  
Total Potential ◽  
Concealed Karst Cave ◽  
The Stability ◽  
Rock Strata

Based on the catastrophe theory, a research method of safe distance between concealed karst cave and tunnel is put forward. The stability of rock stratum between concealed karst cave and tunnel is evaluated by the catastrophe theory, the catastrophe mode of rock strata system destabilization is established through the research of rock stratum total potential energy between karst cave and tunnel, then the safe distance calculation formula between concealed karst cave and tunnel are deduced, which is veried by an engineering example.

scholarly journals Roof Failure Mechanism and Control Technology of Large Section Open-Off Cut in Soft Rock Strata with Thin Thickness

2021 ◽  
Vol 2021 ◽  
pp. 1-16
Author(s):  
Chen Li ◽  
Jun Li ◽  
Xiaoyong Lian ◽  
Yongen Li ◽  
Qi Xue ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Failure Mechanism ◽  
Underground Mining ◽  
Soft Rock ◽  
Mechanical Analysis ◽  
Field Monitoring ◽  
Surrounding Rock ◽  
Engineering Practice ◽  
Control Effect ◽  
Rock Strata

The open-off cut is used for equipment installation of working face before underground mining, and its sectional size is larger than that of the mining roadway. Therefore, the stability of open-off cut surrounding rock determines whether the panel can be put into operation. To solve the roof instability of open-off cut in the Wanli No.1 coal mine, the roof failure mechanism of open-off cut under weak composite rock strata with thin thickness was studied by field monitoring, theoretical analysis, and numerical simulation. First, the characteristics of surrounding rock and the basic law of strata behaviors were obtained by detailed field monitoring. Afterward, FLAC3D numerical simulation and mechanical analysis were used to obtain the main mechanical control parameters of surrounding rock instability, and the existence of a soft interlayer above the roof is the main cause of roof instability. Based on this, the supporting parameters of the open-off cut were optimized and adjusted. The optimized parameters were applied to the adjacent 31207 open-off cut. The engineering practice showed that the optimized supporting parameters have an ideal control effect on roof stability.

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