【摘要】：巷道(承擔著通風、運輸、行人及其他功能)在煤礦開采中扮演著重要的角色,巷道的穩(wěn)定關(guān)系著煤礦的安全和高效生產(chǎn)。近年來由于開采強度的增大和開采深度的增加,加上復雜的地質(zhì)條件,采動應力和構(gòu)造應力的疊加,使得井下開采區(qū)域巷道容易產(chǎn)生大的變形、失穩(wěn)和破壞,甚至會由于沖擊地壓、礦震或強烈礦壓顯現(xiàn)等造成巷道的損壞。如何對處于應力影響范圍內(nèi)的巷道的穩(wěn)定進行監(jiān)測,及時對巷道變形、失穩(wěn)等危險狀況作出預警,是煤礦安全監(jiān)測中的重要研究內(nèi)容。針對巷道變形失穩(wěn)監(jiān)測的實際,本文建立巷道圍巖變形破壞模擬試驗及應變測試系統(tǒng),在通過材料強度配比試驗確定相似模型所需材料最佳配比的基礎(chǔ)上,開展了巷道圍巖變形過程的物理相似模擬研究,測試了二向載荷條件下受載巷道模型變形破壞過程中的宏觀應力、應變的變化特征,同時利用預先植入的光纖光柵傳感器測試了巷道圍巖內(nèi)部應變的變化特征;并結(jié)合RFPA數(shù)值模擬結(jié)果,分析了巷道圍巖變形破壞機理;最后根據(jù)巷道圍巖內(nèi)部彎曲拉伸應變變化的時序特征,提出了基于內(nèi)部應變監(jiān)測的圍巖失穩(wěn)判別條件。全文主要取得以下研究成果:(1)進行了試驗模型所需相似材料的強度配比實驗,測定了沙子石蠟混合物8種配比情況下的主要力學參數(shù),確定了沙子/石蠟為100:12作為相似模型所需材料的最佳配比。(2)建立了巷道圍巖變形破壞模擬試驗系統(tǒng),開展了巷道圍巖變形過程的物理相似模擬試驗,模型整體變形破壞過程的全應力應變曲線可以劃分為四個階段:壓密階段、受載階段、破壞階段和破壞后階段。(3)測試并分析了巷道模型受載變形破壞過程中頂板下沉和支撐壓力變化情況,以及垂向、橫向載荷變化特征和圍巖內(nèi)部應變變化特征。(4)應用RFPA2D軟件,對巷道模型進行了平面應力分布集中及平面裂紋生成發(fā)育擴展過程的數(shù)值模擬分析。(5)提出了基于內(nèi)部應變監(jiān)測的巷道圍巖失穩(wěn)判別條件:①應變呈漸增大趨勢且其絕對值達到很大或者應變值在短時間內(nèi)迅速增大;②應變表現(xiàn)出先上升后下降的趨勢特征,或出現(xiàn)不規(guī)則的波動。本文為巷道圍巖的實驗模擬研究提供了新的思路,對深入了解巷道變形破壞及圍巖失穩(wěn)具有重要的理論價值和現(xiàn)實意義。
[Abstract]:Roadway (with ventilation, transportation, pedestrian and other functions) plays an important role in coal mining, the stability of roadway is related to the safety and efficient production of coal mine. In recent years, due to the increase of mining intensity and the increase of mining depth, coupled with complex geological conditions, the superposition of mining stress and structural stress makes the roadway in underground mining area easy to produce large deformation, instability and destruction. It can even cause roadway damage due to rock burst, mine earthquake or strong rock pressure behavior. How to monitor the stability of roadway under the influence of stress and give early warning to the dangerous condition of roadway deformation and instability is an important research content in coal mine safety monitoring. In view of the reality of deformation and instability monitoring of roadway, a simulation test and strain test system for deformation and failure of surrounding rock of roadway is established in this paper. On the basis of determining the best proportion of materials required by similar model through material strength matching test, The physical similarity simulation of deformation process of roadway surrounding rock is carried out, and the variation characteristics of macroscopic stress and strain in deformation and failure process of loaded roadway model under two-way load are tested. At the same time, the strain variation characteristics of surrounding rock of roadway were tested by pre-implanted fiber grating sensor. Combined with the results of RFPA numerical simulation, the deformation and failure mechanism of roadway surrounding rock is analyzed, and finally, according to the time series characteristics of the deformation and tensile strain change of roadway surrounding rock, the condition for determining the instability of surrounding rock based on internal strain monitoring is put forward. The main results of this paper are as follows: (1) the strength proportioning experiment of similar materials required for the test model was carried out, and the main mechanical parameters of sand paraffin mixture were measured under the condition of 8 kinds of mix ratio. The optimum proportion of sand / paraffin as the material needed for similar model is determined. (2) the simulation test system of deformation and failure of surrounding rock of roadway is established, and the physical similarity simulation test of deformation process of surrounding rock of roadway is carried out. The total stress-strain curves of the whole deformation and failure process of the model can be divided into four stages: compaction stage, loading stage, The failure stage and the post-failure stage. (3) the change of roof subsidence and support pressure and vertical direction in the process of deformation and failure of roadway model under load are tested and analyzed. The variation characteristics of transverse load and strain in surrounding rock. (4) using RFPA2D software, The numerical simulation and analysis of plane stress distribution concentration and plane crack growth are carried out for the tunnel model. (5) the criterion of surrounding rock instability based on internal strain monitoring is put forward: 1 the strain increases gradually. Trend and its absolute value is very large or strain value increases rapidly in a short time; (2) the strain showed a tendency of rising first and then decreasing, or appeared irregular fluctuation. This paper provides a new train of thought for the experimental simulation of roadway surrounding rock, and has important theoretical and practical significance for further understanding the deformation and failure of roadway and the instability of surrounding rock.
【學位授予單位】：中國礦業(yè)大學
【學位級別】：碩士
【學位授予年份】：2015
【分類號】：TD353

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本文編號：2437419