本文選題：循環(huán)冷加載　切入點(diǎn)：裂隙結(jié)構(gòu)　出處：《煤炭學(xué)報(bào)》2017年09期

【摘要】：煤體是具有孔隙、裂隙結(jié)構(gòu)的固體介質(zhì),孔隙的貫通程度、裂隙的寬度是煤層滲透能力的重要指標(biāo),為了使煤體裂隙結(jié)構(gòu)發(fā)生損傷而達(dá)到增透的目的,對(duì)三軸受載煤樣進(jìn)行注液氮冷加載實(shí)驗(yàn),利用液氮注入鉆孔煤實(shí)驗(yàn)裝置系統(tǒng)對(duì)煤樣施加4 MPa圍壓,分別進(jìn)行多周期冷加載作用,通過(guò)高倍相機(jī)、金相顯微鏡、聲波測(cè)速儀和CT成像系統(tǒng)觀測(cè)煤樣表面裂隙寬度、波速衰減率及內(nèi)部結(jié)構(gòu)損傷情況。根據(jù)單軸壓縮實(shí)驗(yàn)的應(yīng)力-應(yīng)變曲線,分析煤樣結(jié)構(gòu)隨冷加載周期的變化規(guī)律。結(jié)果表明:(1)煤樣裂隙結(jié)構(gòu)損傷程度隨冷加載周期的增加而增大,損傷速率隨注液氮周期的增加呈現(xiàn)先增加后降低的非線性變化規(guī)律;(2)煤樣經(jīng)6周期注液氮冷加載后表面發(fā)生顆粒脫落,經(jīng)過(guò)7周期注液氮冷加載后發(fā)生宏觀碎裂;(3)冷加載對(duì)煤樣原生裂隙損傷效果顯著,并沿著層理方向延伸。液氮冷加載能使煤體結(jié)構(gòu)發(fā)生顯著損傷,這為沖擊地壓災(zāi)害防治與瓦斯治理提供了新的方法。
[Abstract]:Coal is a solid medium pore, fracture pore structure, through the degree, the width of the fracture is an important index of coal seam permeability, in order to make the coal fracture structure damage and achieve the purpose of increasing permeability, loading coal injection liquid nitrogen cold loading experiment of three axes, using liquid nitrogen drilling coal injection system the experimental device applied 4 MPa confining pressure of coal samples, respectively. Effect of multi cycle cooling load, through high magnification camera, microscope, width of acoustic velocity meter and CT imaging observation system of coal surface crack, wave attenuation rate and internal structure damage situation. According to the stress-strain curve under uniaxial compression experiment, analysis the structure of coal changes with cold loading cycles. The results showed that: (1) the degree of structural damage fracture of coal samples increases with cold loading cycles, the damage rate is nonlinear first increase and then decrease with the increase of liquid nitrogen cycle Changes in the law; (2) coal samples after 6 cycle injection liquid nitrogen cooled after loading the surface particles, after 7 cycles of loading after injection of liquid nitrogen cooled macro fragmentation; (3) the cold load significantly on the coal crack damage effect, and extends along the direction of loading. Liquid nitrogen cold can make the coal structure significantly damage and this provides a new method for prevention of shock and gas pressure disaster management.

【作者單位】： 遼寧工程技術(shù)大學(xué)力學(xué)與工程學(xué)院;河北科技大學(xué)建筑工程學(xué)院;
【基金】：國(guó)家自然科學(xué)基金資助項(xiàng)目(51704142,51474121,51574139)
【分類(lèi)號(hào)】：TD324.1;TD712
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本文編號(hào)：1659579