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Restraint effect of partition wall on the tunnel floor heave in layered rock mass

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Journal of Mountain Science 2024年第7期21卷 2462-2479页

作者： YANG Yunyun HUANG Da ZHONG Zhu LIU Yang PENG Jianbing School of Civil and Transportation Engineering Hebei University of TechnologyTianjin 300401China College of Geology Engineering and Geomatics Chang’an UniversityXi’an 710054China College of Civil Engineering&Architecture China Three Gorges UniversityYichang 443002China.

The presence of horizontal layered rocks in tunnel engineering significantly impacts the stability and strength of the surrounding rock mass,leading to floor heave in the *** study focused on preparing layered specimens of rock-like material with varying thickness to investigate the failure behaviors of tunnel *** results indicate that thin-layered rock mass exhibits weak interlayer bonding,causing rock layers near the surface to buckle and break upwards when subjected to horizontal *** an increase in the layer thickness,a transition in failure mode occurs from upward buckling to shear failure along the plane,leading to a noticeable reduction in floor heave *** primary cause of significant deformation in floor heave is upward buckling *** address this issue,the study proposes the installation of a partition wall in the middle of the floor to mitigate heave deformation of the rock *** results demonstrate that the partition wall has a considerable stabilizing effect on the floor,reducing the zone of buckling failure and minimizing floor heave *** is crucial for the partition wall to be sufficiently high to prevent buckling failure and ensure *** simulation calculations on an engineering example,it is confirmed that implementing a partition wall can effectively reduce floor heave and enhance the stability of tunnel floor.

关键词： Layered rock floor heave Horizontal compression test Failure behavior Partition wall

Study on mechanism of reinforcing sides to control floor heave of extraction opening

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Journal of Coal Science & Engineering(China) 2005年第1期11卷 1-3页

作者：冯涛 School of Energy and Safety Engineering Hunan University of Science and Technology

Roadway surrounding rock is a compound structure consisted of roof, floor and sides. The sides of extraction opening is the weak coal mass, which affect immediately the stability of floor. It was simulated by numerical calculation for the strength of sides coal to affect the floor heave, the higher strength of sides coal is, the lower degree of floor heave was. So it was put forward reinforcing sides to control floor heave of extraction opening, and it was proved by engineering practice that the floor heave of deep extraction opening can be controlled to a certain degree by reinforcing sides of roadway.

关键词： extraction opening floor heave reinforcing sides

Numerical analysis on water-inrush process due to floor heave

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Journal of Coal Science & Engineering(China) 2008年第2期14卷 225-229页

作者：郭保华 School of Energy Science and Engineering Henan Polytechnic UniversityJiaozuo 454010China

To investigate the water-inrush process due to floor heave,simulation model was made and factors of mining height,immediate roof strength,water pressure,depth and strength of confiningbed,excavation step distance and bury depth were analyzed by using UDEC *** zones theory (containing two maximum main stress circles and three maximum main stress stratiform zones) along excavation direction was proposed, and two-ends-fixed beam mechanical model in maximum main stress circle was estab- *** is found that water inrush always occurs at the end of the beam where shear stress is higher,that is to say,it always occurs at near the starting cut and working face. Water pressure,height and strength of confiningbed are the determined factors,and min- ing height,immediate roof strength,excavation step distance and bury depth effect water inrush process due to floor heave.

关键词： water inrush floor heave simulation mode

Mechanics model and numerical analysis of floor heave in soft rock roadway

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Journal of Coal Science & Engineering(China) 2011年第4期17卷 372-376页

作者： ZHU Chuan-qu WANG Yong CHEN Miao-ming CHEN Zhi WANG Hong-ming Hunan Key Laboratory of Safe Mining Techniques of Coal Mines Hunan University of Science and Technology Xiangtan411201 China

The mechanism of floor heave was analyzed by establishing mechanics models and solving differential equations. The amount of floor heave is proportional to the abutment pressure of surrounding rock, roadway width, and the distance of support pressure peak to the roadway and is inversely proportional to the elastic modulus of floor rock. Using FLAC2D to simulate floor rock grouting in soft rock roadway verifies the active role of floor rock grouting in the floor controlling of soft rock roadway; floor rock grouting and grouting range directly impact on the stability scope of surrounding rock, namely, with the increase of grouting range, the subsidence of roof, the approach of both sides, and the amount of floor heave decreased gradually, the stability of surrounding rock is enhanced

关键词： soft rock roadway floor heave floor rock grouting numerical simulation

Control technology for floor heave of Jurassic soft rock in the Erdos Basin of China: A case study

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Journal of Central South University 2022年第12期29卷 4051-4065页

作者： WEN Zhi-jie JING Suo-lin MENG Fan-bao JIANG Yu-jing State Key Laboratory of Mining Disaster Prevention and Control Co-founded by Shandong Province and the Ministry of Science and Technology Shandong University of Science and TechnologyQingdao 266590China College of Mechanical and Electronic Engineering Shandong University of Science and TechnologyQingdao 266590China

The deformation of soft rock roadway caused by floor heave is a major challenge for coal mines in China western mining areas. To achieve security and stability of soft rock roadway, this work considered the headgate at panel 11505 of the Yushujing Coal Mine as background. First, based on the limit equilibrium method and slip line field theory,a model of floor heave was established, the mechanism of floor heave control was analyzed, and an optimized support method was proposed. Then, the displacement, stress and failure zones around the surrounding rock with the original and optimized support were studied by FLAC. Finally, the serviceability of the support method was verified by field application. The results showed that the main deformation form of soft rock roadway is floor heave, and 0.5 m is relatively reasonable thicknesses of the inverted arch. The extrusion failure zone and shear failure zone were mainly affected by tensile and shear failure, respectively. The modification of floor and the effective support are key points. The failure zone was consistent between numerical simulation and theoretical calculation. The maximum convergences of floor heave determined by numerical simulation and field measurement were 220 mm and 240 mm, respectively, which were reduced by 55% and 60% compared with the original support, and the convergence between sidewalls decreased considerably. The optimized support method controls the floor heave well.

关键词： soft rock roadway floor heave mechanical model control mechanism optimized support

Study of mechanical principle of floor heave of roadway driving along next goaf in fully mechanized sub-level caving face

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Journal of Coal Science & Engineering(China) 2001年第1期7卷 13-17页

作者：王卫军侯朝炯 XiangtanPolytechnicUniversity Xiangtan411201China ChinaUniversityofMiningandTechnology Xuzhou221008China

Abstract On the basis of analyzing floor strata mechanical circumstance of the roadway, the mechanical model was established. The relative displacement of roadway floor, narrow pillar floor coal mass and floor strata was calculated, the results showed that the high abutment pressure on coal mass beside the roadway was the main reason to lead to relative displacement of floor strata. And the roadway floor heave come mainly from three aspects. Firstly, the roadway floor strata is easily fractured by the stretch stress. Secondly, because the high abutment pressure is greater than the uniaxial compressive strength of floor strata, when the roadway floor strata are fractured, the coal mass floor strata at the same depth will be fractured, and broken rock will fluid into the open roadway. Thirdly, comparing with the coal mass floor, the roadway floor is relative ascending.

关键词： floor heave roadway driving along next goaf in coal face with fully mechanized top coal caving mechanical principle

Application of the coal mine floor rating(CMFR)to assess the floor stability in a Central Appalachian Coal Mine

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International Journal of Mining Science and Technology 2021年第1期31卷 83-89页

作者： Sena Cicek Ihsan Berk Tulu Mark Van Dyke Ted Klemetti Joe Wickline Department of Mining Engineering West Virginia UniversityMorgantownWV 26505USA National Institute for Occupational Safety and Health Pittsburgh Mining Research DivisionPittsburghPA 15236USA Coronado Global Resources Inc. BeckleyWV 25801USA

Estimating the overall floor stability in a coal mine using deterministic methods which require complex engineering properties of floor strata is desirable,but generally it is impractical due to the difficulty of gathering essential input ***,applying a quantitative methodology to describe floor quality with a single number provides a practical estimate for preliminary assessment of floor *** coal mine floor rating(CMFR)system,developed by the University of New South Wales(UNSW),is a rockmass classification system that provides an indicator for the competence of floor *** most significant components of the CMFR are uniaxial compressive strength and discontinuity intensity of floor *** addition to the competence of the floor,depth of cover and stress notch angle are input parameters used to assess the preliminary floor *** this study,CMFR methodology was applied to a Central Appalachian Coal Mine that intermittently experienced floor *** drill core data,overburden maps,and mine plans were utilized for the ***,qualitative data(failure/non-failure)on floor conditions of the mine entries near the core holes was collected and analyzed so that the floor quality and its relation to entry stability could be estimated by statistical *** was found that the current CMFR classification system is not directly applicable in assessing the floor stability of the Central Appalachian Coal *** order to extend the applicability of the CMFR classification system,the methodology was modified.A calculation procedure of one of the CMFR classification system’s components,the horizontal stress rating(HSR),was changed and new parameters were added to the HSR.

关键词： Rock mass classification Coal mine floor rating(CMFR) floor heave floor failure Buckling failure mechanism

Analytical solution for stress and deformation of the mining floor based on integral transform

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International Journal of Mining Science and Technology 2015年第4期25卷 581-586页

作者： Feng Qiang Jiang Binsong State Key Laboratory of Geomechanics and Deep Underground Engineering China University of Mining & Technology Civil Engineering and Architecture Shandong Key Laboratory of Civil Engineering Disaster Prevention & Mitigation Shandong University of Science and Technology

Following exploitation of a coal seam, the final stress field is the sum of in situ stress field and an excavation stress field. Based on this feature, we firstly established a mechanics analytical model of the mining floor strata. Then the study applied Fourier integral transform to solve a biharmonic equation,obtaining the analytical solution of the stress and displacement of the mining floor. Additionally, this investigation used the Mohr–Coulomb yield criterion to determine the plastic failure depth of the floor strata. The calculation process showed that the plastic failure depth of the floor and floor heave are related to the mining width, burial depth and physical–mechanical properties. The results from an example show that the curve of the plastic failure depth of the mining floor is characterized by a funnel shape and the maximum failure depth generates in the middle of mining floor; and that the maximum and minimum principal stresses change distinctly in the shallow layer and tend to a fixed value with an increase in depth. Based on the displacement results, the maximum floor heave appears in the middle of the stope and its value is 0.107 m. This will provide a basis for floor control. Lastly, we have verified the analytical results using FLAC3 Dto simulate floor excavation and find that there is some deviation between the two results, but their overall tendency is consistent which illustrates that the analysis method can well solve the stress and displacement of the floor.

关键词： Integral transform Mining floor Plastic failure depth floor heave Analytical solution

Stress and deformation analysis of gob-side pre-backfill driving procedure of longwall mining:a case study

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International Journal of Coal Science & Technology 2021年第6期8卷 1351-1370页

作者： Rui Wu Penghui Zhang Pinnaduwa H.S.W.Kulatilake Hao Luo Qingyuan He School of Resources and Environmental Engineering Jiangxi University of Science and TechnologyGanzhou 341000China State Key Laboratory of Coal Resources and Safe Mining School of MinesChina University of Mining and TechnologyXuzhou 221116China

At present,non-pillar entry protection in longwall mining is mainly achieved through either the gob-side entry retaining(GER)procedure or the gob-side entry driving(GED)*** GER procedure leads to difficulties in maintaining the roadway in mining both the previous and current panels.A narrow coal pillar about 5-7 m must be left in the GED procedure;therefore,it causes permanent loss of some *** gob-side pre-backfill driving(GPD)procedure effectively removes the wasting of coal resources that exists in the GED procedure and finds an alternative way to handle the roadway maintenance problem that exists in the GER *** FLAC^(3D) software was used to numerically investigate the stress and deformation distributions and failure of the rock mass surrounding the previous and current panel roadways during each stage of the GPD procedure which requires"twice excavation and mining".The results show that the stress distribution is slightly asymmetric around the previous panel roadway after the"primary excavation".The stronger and stiffer backfill compared to the coal turned out to be the main bearing body of the previous panel roadway during the"primary mining".The highest vertical stresses of 32.6 and 23.1 MPa,compared to the in-situ stress of 10.5 MPa,appeared in the backfill wall and coal seam,*** the"primary mining",the peak vertical stress under the coal seam at the floor level was slightly higher(18.1 MPa)than that under the backfill(17.8 MPa).After the"secondary excavation",the peak vertical stress under the coal seam at the floor level was slightly lower(18.7 MPa)than that under the backfill(19.8 MPa);the maximum floor heave and maximum roof sag of the current panel roadway were 252.9 and 322.1 mm,*** the"secondary mining",the stress distribution in the rock mass surrounding the current panel roadway was mainly affected by the superposition of the front abutment pressure from the current panel and the side abutment p

关键词： Gob-side pre-backfill driving procedure floor heave Roadway stability Stress distribution Abutment pressure