不同初始應力下卸荷煤體氧化特性
發(fā)布時間：2018-10-24 12:55
【摘要】：為探討不同初始應力下卸荷煤體氧化特性,采用程序升溫實驗、煤巖三軸蠕變實驗、壓汞實驗對易自燃原煤樣及其不同初始應力下卸荷煤樣進行微觀氧化特性對比研究。結果表明:宏觀方面,不同初始應力下卸荷煤體比原始煤樣更容易氧化,特征溫度點下各實驗煤樣的CO產生量-應變曲線與軸應力-應變曲線具有相似的規(guī)律,且煤樣氧化能力隨初始應力大小變化曲線呈"駝峰狀",當初始應力達到15 MPa,煤巖處于塑性變形裂隙擴展階段,煤樣卸荷后與氧氣接觸能力顯著增強;初始應力達到25 MPa,煤巖處于應變軟化階段,煤樣卸荷后與氧氣接觸能力最強,間接增強了煤樣的氧化能力。不同初始應力下卸荷煤體的特征溫度點均提前于原始煤樣,使得發(fā)生氧化自燃的時間提前。微觀方面,煤體總孔容和孔徑分布共同制約著氧化反應進程,初始應力使煤體的孔容積、孔徑增大,小孔和微孔是O_2與煤基質氧化反應區(qū)域的主要貢獻者,小孔、微孔孔容值和比表面積隨初始應力的變化趨勢與實驗煤樣氧化能力隨初始應力變化趨勢相同。根據實驗結果,隨著煤層埋深增大,地應力增高,采動卸荷后煤體氧化危險程度增大;當煤層賦存地應力隨埋深達到臨界值后,采動卸荷后煤體氧化危險性程度將會降低;對于同一開采水平,應力相對集中區(qū)卸荷后煤體將更易發(fā)生氧化自燃,其氧化難易程度與煤體強度、賦存應力存在一定關聯(lián)。
[Abstract]:In order to study the oxidation characteristics of unloaded coal under different initial stresses, the micro-oxidation characteristics of unloaded coal samples under different initial stresses were studied by temperature programmed test, triaxial creep test and mercury injection test. The results show that unloading coal under different initial stress is easier to be oxidized than the original coal sample under different initial stress. The CO yield and strain curves of experimental coal samples at characteristic temperature have similar laws to those of axial stress-strain curves. When the initial stress reaches 15 MPa, the oxidation capacity of coal sample is in the stage of plastic deformation and crack extension, and the contact ability of coal sample with oxygen is obviously enhanced after unloading. The initial stress of 25 MPa, is in the strain softening stage, and the contact ability of coal sample with oxygen is the strongest after unloading, which indirectly enhances the oxidation ability of coal sample. The characteristic temperature point of unloading coal under different initial stress is earlier than that of the original coal sample, which makes the time of spontaneous combustion of oxidation ahead of time. Microscopically, the total pore volume and pore size distribution of coal body jointly restrict the oxidation reaction process. The initial stress makes the pore volume and pore diameter of coal body increase, and the pore and micropore are the main contributors of oxidizing reaction region between O _ 2 and coal matrix. The change trend of pore volume and specific surface area with initial stress is the same as that of experimental coal sample. According to the experimental results, with the increase of coal seam depth and the increase of in-situ stress, the degree of oxidation hazard of coal body increases after mining and unloading, and the degree of oxidation hazard of coal body will be reduced after mining and unloading when the buried stress of coal seam reaches the critical value. For the same mining level, the oxidation spontaneous combustion of coal will occur more easily after unloading in the stress relative concentration area, and the degree of oxidation difficulty is related to the strength of coal body and the existing stress.
【作者單位】： 河南理工大學安全科學與工程學院;煤炭安全生產河南省協(xié)同創(chuàng)新中心;重慶大學煤礦災害動力學與控制國家重點試驗室;河南理工大學機械與動力工程學院;
【基金】：國家自然科學基金資助項目(51304070,51674103,U1361205)
【分類號】：TD752.2
本文編號：2291477
[Abstract]:In order to study the oxidation characteristics of unloaded coal under different initial stresses, the micro-oxidation characteristics of unloaded coal samples under different initial stresses were studied by temperature programmed test, triaxial creep test and mercury injection test. The results show that unloading coal under different initial stress is easier to be oxidized than the original coal sample under different initial stress. The CO yield and strain curves of experimental coal samples at characteristic temperature have similar laws to those of axial stress-strain curves. When the initial stress reaches 15 MPa, the oxidation capacity of coal sample is in the stage of plastic deformation and crack extension, and the contact ability of coal sample with oxygen is obviously enhanced after unloading. The initial stress of 25 MPa, is in the strain softening stage, and the contact ability of coal sample with oxygen is the strongest after unloading, which indirectly enhances the oxidation ability of coal sample. The characteristic temperature point of unloading coal under different initial stress is earlier than that of the original coal sample, which makes the time of spontaneous combustion of oxidation ahead of time. Microscopically, the total pore volume and pore size distribution of coal body jointly restrict the oxidation reaction process. The initial stress makes the pore volume and pore diameter of coal body increase, and the pore and micropore are the main contributors of oxidizing reaction region between O _ 2 and coal matrix. The change trend of pore volume and specific surface area with initial stress is the same as that of experimental coal sample. According to the experimental results, with the increase of coal seam depth and the increase of in-situ stress, the degree of oxidation hazard of coal body increases after mining and unloading, and the degree of oxidation hazard of coal body will be reduced after mining and unloading when the buried stress of coal seam reaches the critical value. For the same mining level, the oxidation spontaneous combustion of coal will occur more easily after unloading in the stress relative concentration area, and the degree of oxidation difficulty is related to the strength of coal body and the existing stress.
【作者單位】： 河南理工大學安全科學與工程學院;煤炭安全生產河南省協(xié)同創(chuàng)新中心;重慶大學煤礦災害動力學與控制國家重點試驗室;河南理工大學機械與動力工程學院;
【基金】：國家自然科學基金資助項目(51304070,51674103,U1361205)
【分類號】：TD752.2
【相似文獻】
相關期刊論文 前1條
1 劉殿書,王萬富,楊呂俊,謝夫海;初始應力條件下爆破機理的動光彈實驗研究[J];煤炭學報;1999年06期
，本文編號：2291477
本文鏈接：http://sikaile.net/kejilunwen/anquangongcheng/2291477.html
