本文選題：煤田火區(qū) + 單軸壓縮�。� 參考：《西安科技大學(xué)》2017年碩士論文

【摘要】：現(xiàn)在煤田火災(zāi)的防治己是全世界廣泛研究的熱點和急需解決的重大難題。加強煤田火區(qū)形成演化過程的研究,實現(xiàn)煤田火災(zāi)非控燃燒特性的定性描述向定量表達的轉(zhuǎn)化具有重要的意義。本文采用實驗研究的方法,對火區(qū)煤巖體在熱力耦合作用下的力學(xué)特性進行研究,確定適用于煤田火災(zāi)溫度場及應(yīng)力場演化的相似材料及其配比,通過相似模擬試驗分析煤田火災(zāi)溫度場和應(yīng)力場的演化過程,主要的研究內(nèi)容如下:運用MTS880電液伺服材料試驗系統(tǒng)進行單軸壓縮實驗,實驗分析活雞兔火區(qū)煤巖體在熱力耦合作用下的物理力學(xué)特征。在處理溫度從常溫升高到400℃時,巖樣峰值應(yīng)力由60.04MPa上升到77.36MPa,增幅達28.85%;在25℃-400℃之間,巖樣峰值應(yīng)變由0.762×10-2增加到1.458×10-2,增幅達91.3%;在處理溫度由25℃升高到400℃的過程中,巖樣彈性模量由4.86GPa增加到7.72GPa,增幅達58.8%;煤樣峰值應(yīng)力隨溫度先增大后減小,當(dāng)煤樣處理溫度達到200℃時,峰值應(yīng)力再次隨處理溫度增加而增大,當(dāng)溫度進一步增加后,又逐漸降低。從多角度對不同相似材料進行對比分析,運用正交實驗方法研究適用于煤田火災(zāi)溫度場和應(yīng)力場演化的相似材料。實驗結(jié)果表明鐵粉添加量對試樣導(dǎo)熱系數(shù)的影響最顯著,可以通過調(diào)節(jié)相似材料中鐵粉的添加量來使模型與原型熱相似;選擇石英砂為骨料,選用石膏和大白粉作為膠結(jié)物�；谧灾鳂�(gòu)建的煤田火災(zāi)溫度場及應(yīng)力場演化相似試驗平臺,通過試驗得出:煤層中高溫區(qū)域位于加熱源正上方,煤層溫度場經(jīng)歷了常溫區(qū)、增溫區(qū)、高溫區(qū)和降溫區(qū)的變化過程;上覆巖層高溫區(qū)域位于巖層模型的中心處,溫度變化規(guī)律與煤層類似,先升高后趨于平穩(wěn);模型中高應(yīng)力區(qū)域主要位于燃燒區(qū)附近,并且高應(yīng)力區(qū)域隨著燃燒的推進而向前推進,但應(yīng)力的變化規(guī)律與溫度的變化規(guī)律并不完全一致;在溫度場和應(yīng)力場的共同作用下,模型上覆巖層中形成微破裂,隨著燃燒的繼續(xù),這些微破裂將逐漸擴展,進而產(chǎn)生剪切斷裂,最后發(fā)生垮落失穩(wěn)的現(xiàn)象。
[Abstract]:The prevention and control of coalfield fire has become a hot spot and a major problem to be solved in the world. It is of great significance to strengthen the study on the formation and evolution process of the coal-field fire area and to realize the transformation from qualitative description to quantitative expression of the non-controlled combustion characteristics of the coal-field fire. In this paper, the mechanical properties of coal and rock mass under thermal coupling are studied by means of experimental study, and the similar materials and their proportions suitable for the evolution of temperature field and stress field in coal field are determined. The evolution process of temperature field and stress field of coal-field fire is analyzed by similar simulation test. The main contents are as follows: uniaxial compression experiment is carried out by using MTS880 electro-hydraulic servo material test system. The physical and mechanical characteristics of coal and rock mass under thermal coupling were analyzed experimentally. The peak stress of rock samples increased from 60.04MPa to 77.36 MPa from normal temperature to 400 鈩，

本文編號：1940179