Geohazard Mechanics最新文献

{"title":"Detection and targeted control of regional stress field for coal burst prevention","authors":"Linming Dou ,&nbsp;Zhenyu Sun ,&nbsp;Xuwei Li ,&nbsp;Quan Liu ,&nbsp;Siyuan Gong ,&nbsp;Chao Wang","doi":"10.1016/j.ghm.2022.11.006","DOIUrl":"https://doi.org/10.1016/j.ghm.2022.11.006","url":null,"abstract":"<div><p>As coal burst normally occurs in the area of high stress concentration, it is of significance to study the features of regional stress field in coal mines. Primitive stress field, mining-induced stress field and their coupling effect are investigated through the methods of theoretical analysis, field measurement, numerical simulation and wave velocity CT inversion, and the relationship among regional stress field, high-energy seismic events and coal bursts are analyzed. Investigation of the 3# mining district in Xingcun coal mine shows that: (1) Though stress concentration changes in the mining process, several special areas witnesses stress concentration in the whole mining process, such as the rise pillar area, several syncline axis areas and large fault areas; (2) Coal burst occurrence and high-energy seismic events have a close relationship with regional stress field. Coal bursts and high-energy seismic events tend to occur in areas of stable stress concentration, such as the rise area, several syncline axis areas and large fault areas. Targeted control of stress field for coal burst prevention is developed based on stress field detection. The process of targeted control of stress field for coal burst prevention is: detection of regional stress field based mainly on wave velocity CT, identification of stress concentration, implementation of destress measures to control the identified stress concentration. This method of stress field control was applied to LW3306 working face in Xingcun coal mine and coal burst hazards were effectively controlled in LW3306.</p></div>","PeriodicalId":100580,"journal":{"name":"Geohazard Mechanics","volume":"1 1","pages":"Pages 69-76"},"PeriodicalIF":0.0,"publicationDate":"2023-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49904679","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Pendulum waves and basics of «geomechanical thermodynamics»","authors":"V.N. Oparin","doi":"10.1016/j.ghm.2022.12.001","DOIUrl":"https://doi.org/10.1016/j.ghm.2022.12.001","url":null,"abstract":"<div><p>It is shown that modern achievements in the field of experimental and theoretical researches and developments of innovative measuring systems for monitoring of non-linear dynamic and kinematic characteristics allow to formulate basics of new academic discipline, designated as “geomechanical thermodynamics”. The following circumstances can be considered as the most important prerequisites for development of this new discipline.</p><p>(1) Practical completeness of the classical thermodynamics, based on kinetic gas theory and molecular movements in solid bodies; (2) Creation of “formular construction tool” for the description of dynamic and kinematic characteristics of pendulum waves and energy conditions of their occurrence and propagation from dynamic sources, located in multi-phased stressed rock mass and geomaterials with block-hierarchical structure; (3) Principal opportunity to establish formal relations between substantial energy carriers of “packages” of non-linear pendulum waves (geoblocks of certain hierarchical levels according to their diameters) and “molecules”: their movement, velocity and acceleration of the “molecules” ↔ “geoblock”; “force interactions between molecules” ↔ “non-linear elastic interaction between geoblocks”, etc.</p><p>The term of “geomechanical temperature” is introduced and its analytical expression, which is proportional to kinetic energy of movement of geoblocks with defined volume for their hierarchical subsequence at “confined” conditions of the stressed rock mass, is shown. The similar aspects are discussed, when emission acoustic-electromagnetic fields are fixed using corresponding coefficients of mechanical-electrical and mechanical-acoustic transformations. In order to quantitively describe the evolution of energy state of local zones of stress-strain concentration and surroundings of their non-linear influence from catastrophic events at the natural and mine-engineering systems (earthquakes, rock bursts, etc.), the terms of their geomechanical and thermodynamic stages are introduced and specified: <span><math><mrow><msub><mi>T</mi><mi>i</mi></msub><mrow><mo>(</mo><mrow><mi>i</mi><mo>∈</mo><mn>0</mn><mo>,</mo><mo>+</mo><mo>,</mo><mo>±</mo><mo>,</mo><mo>−</mo><mo>,</mo><mo>∗</mo></mrow><mo>)</mo></mrow></mrow></math></span>‒ with background states <span><math><mrow><mo>(</mo><mrow><mi>i</mi><mo>∈</mo><mn>0</mn><mo>,</mo><mo>∗</mo></mrow><mo>)</mo></mrow></math></span> and three major stages <span><math><mrow><mo>(</mo><mrow><mi>i</mi><mo>∈</mo><mo>+</mo><mo>,</mo><mo>±</mo><mo>,</mo><mo>−</mo></mrow><mo>)</mo></mrow></math></span> outlined, where (+) is the concentration, (±, ‒) are the failure and relaxation and (∗) is the quasi-recovering up to “background” level after the occurred catastrophic event. Using certain examples, the existence of critical elastic energy content of local zones with “meta-stable state”, which is transforming to quasi-resonance process of failure and relaxation of “excessiv","PeriodicalId":100580,"journal":{"name":"Geohazard Mechanics","volume":"1 1","pages":"Pages 38-52"},"PeriodicalIF":0.0,"publicationDate":"2023-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49904671","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Disturbance response instability theory of rock bursts in coal mines and its application","authors":"Yishan Pan,&nbsp;Aiwen Wang","doi":"10.1016/j.ghm.2022.12.002","DOIUrl":"https://doi.org/10.1016/j.ghm.2022.12.002","url":null,"abstract":"<div><p>Aiming at the rock burst prevention in coal mines, this study argue that a rock burst is the instability of the coal mass deformation system with the infinite deformation response subjected to a small disturbance, and the concepts of control, disturbance and response variables of the coal mass deformation system are proposed. The analytical solution of rock bursts of circular roadways is derived, using a mechanical model of the coal mass deformation system of circular roadways, and the stress and energy conditions of the disturbance response instability of a rock burst are also presented. Based on the disturbance response instability theory, this study identifies the factors controlling the occurrence of rock bursts, involving the coal uniaxial compressive strength, coal bursting liability and roadway support stress. The relationship between the critical stress and the critical resistance zone of surrounding rock in roadways, the coal uniaxial compressive strength, roadway support stress, roadway geometric parameters and coal burst liability is revealed, and the critical stress index evaluation method of rock burst risk is proposed. Considering the disturbance and response variables of rockburst occurrence, a monitoring system of rock burst based on stress and energy monitoring is established. Considering managing the disturbance and control variables, regional and local prevention measures of rock burst are proposed from four aspects: destressing in coal mass, avoiding the mutual disturbance between multi-group mining or excavation, reducing the dynamic load disturbance and weakening of the physical properties of the coal mass. Based on the enhancement principle of the roadway support stress on the critical load of rockburst occurrence and the energy absorption effect of the support, an energy absorption and anti-bursting support technology for roadways are proposed. The disturbance response instability theory of rock bursts has formed a technical system from the aspects of mechanism, prediction and prevention to guide the engineering practice for rock burst mitigation.</p></div>","PeriodicalId":100580,"journal":{"name":"Geohazard Mechanics","volume":"1 1","pages":"Pages 1-17"},"PeriodicalIF":0.0,"publicationDate":"2023-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49904672","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Quantitative assessment of energy changes in underground coal excavations using numerical approach","authors":"Chunchen Wei,&nbsp;Chengguo Zhang,&nbsp;Onur Vardar,&nbsp;John Watson,&nbsp;Ismet Canbulat","doi":"10.1016/j.ghm.2022.11.003","DOIUrl":"https://doi.org/10.1016/j.ghm.2022.11.003","url":null,"abstract":"<div><p>Coal burst is caused by a dynamic and unstable release of energy within the overstressed rock mass/coal during the mining process. Although the occurrence of coal burst is a result of the complex impacts of many factors, a major component of coal burst mechanism is associated with energy storage and release. This study reviewed the sources of energy that can contribute to a coal burst, principally strain and potential energy stored in the coal mass around excavations, and radiated seismic energy released by geological discontinuities. The energy balance concept proposed by [1] was utilised in numerical modellings to compute the radiated seismic energy in a modelling system and the kinetic energy of ejected rock/coal for a given burst scenario. The modelling results showed that the strain energy density (SED) around excavations increases with increasing mining depth and the maximum SED area migrates deeper into the coal. For the effect of geological features on both roadway and longwall face, the coal burst risk proneness can be assessed considering the proposed energy terms. According to the results of energy changes in excavations, the modelling predicts that for depths of ejection 2 ​m and 3 ​m the kinetic energy of a burst increases as the mining depth increases from 100 ​m to 1000 ​m, but for depth of ejection 1 ​m only increases until mining depth reaches 700 ​m and then decreases. The proposed energy-based model indicators can deepen the understanding of energy changes and the associated coal burst risks for different mining conditions.</p></div>","PeriodicalId":100580,"journal":{"name":"Geohazard Mechanics","volume":"1 1","pages":"Pages 58-68"},"PeriodicalIF":0.0,"publicationDate":"2023-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49904683","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"An assessment of earthquake vulnerability by multi-criteria decision-making method","authors":"Md. Saalim Shadmaan,&nbsp;Samsunnahar Popy","doi":"10.1016/j.ghm.2022.11.002","DOIUrl":"https://doi.org/10.1016/j.ghm.2022.11.002","url":null,"abstract":"<div><h3>Background</h3><p>Earthquake is one of the most destructive catastrophes in Bangladesh and the evaluation of vulnerability is a prerequisite for the earthquake risk estimation. As a result, determining vulnerability is essential for lowering the future fatalities. The fundamental challenge in estimating the seismic vulnerability is to have a systematic understanding of all potential earthquake related losses. With this objective, the current study deals with evaluating the seismic vulnerability of Sylhet district of Bangladesh.</p></div><div><h3>Method</h3><p>A multi-criteria decision-making approach such as the analytical hierarchy process (AHP) has been used in this study to estimate the earthquake vulnerability. For the assessment of three scenarios namely social, structural, and physical distance vulnerabilities, several criteria have been chosen in order to fully identify the risk of earthquake.</p></div><div><h3>Findings</h3><p>The study uncovers the vulnerable areas of Sylhet district. It is revealed that in terms of social vulnerability, 9% area of Sylhet district is under very high, 55% high, 15% moderate, 17% low, and 4% is under very low vulnerable zone. Structural vulnerability represents that 9% of the district area is under the very high vulnerability category, 48% high, 31% moderate, 4% low, and 8% falls under the very low category zone, whereas physical distance vulnerability comes up with a result that 23%, 38%, 23%, 7%, and 9% of the total area fall into very high, high, moderate, low, and very low categories, respectively.</p></div><div><h3>Interpretation</h3><p>The current work on seismic vulnerability assessment might be useful in reducing the risk and minimizing the losses due to earthquake.</p></div>","PeriodicalId":100580,"journal":{"name":"Geohazard Mechanics","volume":"1 1","pages":"Pages 94-102"},"PeriodicalIF":0.0,"publicationDate":"2023-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49904676","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Experimental investigations on the cracking and mechanical responses of PMMA samples with two 3D embedded elliptic flaws under uniaxial compression","authors":"Xiaoping Zhou,&nbsp;Yunding Long,&nbsp;Wei Ye","doi":"10.1016/j.ghm.2022.11.004","DOIUrl":"https://doi.org/10.1016/j.ghm.2022.11.004","url":null,"abstract":"<div><p>In this paper, the cracking and mechanical responses are studied for the Polymethylmethacrylate (PMMA) sample with two three-dimensional embedded coplanar elliptic flaws subjected to uniaxial compression. The experimental results indicate that both the peak stress and crack initiation stress first decrease and then increase with increasing flaw angle, and they increase linearly with increasing flaw spacing. Moreover, five crack modes occur in these tested samples, including the coplanar secondary cracks, wing cracks, petal cracks, anti-wing cracks, and vertical giant cracks. The growth length of wing cracks is approximately equal to the length of the long axis of pre-existing flaw. However, the maximum width is roughly equal to half the length of the long axis of pre-existing elliptic flaw. The final failure modes include the splitting failure induced by wing cracks and vertical giant cracks, and the mixed tensile-shear failure induced by coplanar secondary cracks and wing cracks.</p></div>","PeriodicalId":100580,"journal":{"name":"Geohazard Mechanics","volume":"1 1","pages":"Pages 77-85"},"PeriodicalIF":0.0,"publicationDate":"2023-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49904677","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}