本文選題：煤與瓦斯突出　切入點(diǎn)：層裂　出處：《中國(guó)礦業(yè)大學(xué)》2014年博士論文

【摘要】：煤與瓦斯突出是含瓦斯煤體在應(yīng)力和瓦斯的綜合作用下發(fā)生的失穩(wěn)破壞。突出過程中，煤體裂隙擴(kuò)展、被剝離破碎拋向采掘空間。因此需對(duì)突出發(fā)展的內(nèi)在機(jī)制進(jìn)行研究，為防治煤與瓦斯突出奠定理論基礎(chǔ)。 本文運(yùn)用表面物理化學(xué)、巖石力學(xué)、滲流力學(xué)和相似理論等多學(xué)科理論，采用理論和實(shí)驗(yàn)相結(jié)合的方法，研究了含瓦斯煤體的吸附/解吸規(guī)律、應(yīng)力場(chǎng)-瓦斯場(chǎng)-溫度場(chǎng)耦合作用下的本構(gòu)關(guān)系和滲透演化規(guī)律，開展了突出模擬試驗(yàn)，研究了突出的層裂發(fā)展機(jī)制，并取得了一定的創(chuàng)新成果。本文的主要研究結(jié)論如下： 實(shí)驗(yàn)研究了臥龍湖煤礦10煤的不同溫度條件下的吸附規(guī)律，得出其吸附常數(shù)a不隨溫度變化，吸附常數(shù)b隨溫度的變化而改變。開展了大量的等溫條件下煤粒瓦斯解吸實(shí)驗(yàn)，解吸量與時(shí)間的平方根之間符合Langmuir形式的方程。 將煤體全應(yīng)力應(yīng)變過程簡(jiǎn)化為線彈性、非線性彈塑性、脆性跌落和理想塑性4個(gè)階段，滲透率演化對(duì)應(yīng)簡(jiǎn)化為滲透率減小段、滲透率增加段、滲透率快速增加階段和滲透率不變段。研究煤體裂隙的內(nèi)部結(jié)構(gòu)，得出煤基質(zhì)的膨脹變形僅有部分作用于煤體裂隙，提出煤基質(zhì)膨脹變形對(duì)裂隙變形的影響因子f m，其值介于0~1之間。構(gòu)建了考慮吸附變形、熱膨脹變形和有效應(yīng)力作用的含瓦斯煤體本構(gòu)方程。基于此建立了含瓦斯煤體線彈性階段和塑性階段的滲透率模型。 基于相似準(zhǔn)則，設(shè)計(jì)了真三軸煤與瓦斯突出模擬試驗(yàn)系統(tǒng)，，其性能參數(shù)為：瓦斯壓力≤10MPa，地應(yīng)力≤27MPa，溫度在室溫至60℃范圍內(nèi)變化。開展了煤與瓦斯突出相似模擬試驗(yàn)。以模擬試驗(yàn)條件為基礎(chǔ)，建立了考慮瓦斯拉裂破壞、吸附膨脹變形和吸附對(duì)煤體強(qiáng)度影響的突出層裂發(fā)展模型。解算突出層裂發(fā)展模型，研究了瓦斯壓力、吸附能力、斷裂韌度和滲透率對(duì)突出發(fā)展的影響規(guī)律。 突出是一個(gè)快速的動(dòng)力過程，模擬得出其發(fā)展時(shí)間一般在1.68s。其發(fā)展過程大致可分為突出發(fā)展的加速期、穩(wěn)定期和衰減期。突出發(fā)動(dòng)后，在高壓瓦斯和瓦斯壓力梯度作用，煤體被快速破壞。此時(shí)煤體的瓦斯壓力梯度最大，煤體破壞產(chǎn)生的層裂的厚度較小。進(jìn)入穩(wěn)定期，突出面前方煤體的壓力分布、破裂速度基本穩(wěn)定。瓦斯壓力梯度區(qū)的寬度平均為7.33cm；瓦斯壓力梯度平均為8.215MPa/m。破裂速度從0.4s的1.32m/s上升至0.9s的1.54m/s。突出向內(nèi)部發(fā)展的速度約為0.15193m/s。 隨著突出的發(fā)展，未被剝離煤體中的瓦斯壓力和梯度逐漸減小，層裂的厚度逐漸增大，最終瓦斯耗盡，突出終止。
[Abstract]:Coal and gas outburst is the instability failure of gas-bearing coal body under the combined action of stress and gas.In the process of outburst, the crack of coal body expands and is stripped and broken and thrown into the excavation space.Therefore, the internal mechanism of outburst development should be studied to lay a theoretical foundation for preventing coal and gas outburst.In this paper, the adsorption / desorption law of gas-bearing coal is studied by means of surface physical chemistry, rock mechanics, seepage mechanics and similarity theory.Under the coupling of stress field gas field and temperature field the constitutive relation and permeability evolution law were studied. The outburst simulation test was carried out and the development mechanism of outburst spallation was studied and some innovative results were obtained.The main conclusions of this paper are as follows:The adsorption law of 10 coal at different temperatures in Wolong Lake Coal Mine is studied experimentally. It is found that the adsorption constant a does not change with the temperature, and the adsorption constant b changes with the change of temperature.A large number of experiments on desorption of coal particle gas under isothermal conditions have been carried out. The desorption amount and the square root of time accord with the equation of Langmuir form.The whole stress-strain process of coal body is simplified into four stages: linear elasticity, nonlinear elastoplasticity, brittle drop and ideal plasticity. The permeability evolution is simplified as the permeability decreasing section and the permeability increasing stage.The stage of rapid increase of permeability and the period of constant permeability.The internal structure of coal body fracture is studied. It is concluded that only part of the expansion deformation of coal matrix acts on coal body fracture. The influence factor f m of the expansion deformation of coal matrix on fracture deformation is put forward, whose value is between 0 and 1.The constitutive equation of gas-bearing coal body considering adsorption deformation, thermal expansion deformation and effective stress is established.Based on this, the permeability models of linear elastic stage and plastic stage of gas-bearing coal body are established.Based on the similarity criterion, a true triaxial coal and gas outburst simulation test system is designed. Its performance parameters are gas pressure 鈮

本文編號(hào)：1716781