本文關(guān)鍵詞：循環(huán)荷載條件下原煤力學(xué)性質(zhì)及損傷演化規(guī)律　出處：《煤炭學(xué)報(bào)》2016年07期 　論文類型：期刊論文

  更多相關(guān)文章： 循環(huán)荷載 單軸和三軸強(qiáng)度試驗(yàn) 聲發(fā)射 損傷演化規(guī)律

【摘要】：對(duì)原煤試樣分別進(jìn)行了常規(guī)加載和循環(huán)荷載條件下的單軸和三軸力學(xué)強(qiáng)度試驗(yàn),借助聲發(fā)射技術(shù),系統(tǒng)研究了單軸循環(huán)荷載及三軸循環(huán)荷載條件下原煤的損傷演化規(guī)律并對(duì)比分析。常規(guī)循環(huán)荷載試驗(yàn)結(jié)果顯示:從循環(huán)初始至結(jié)束,煤巖內(nèi)部損傷過程具有明顯的3階段,即初始損傷階段,微裂紋擴(kuò)展萌生穩(wěn)定增長(zhǎng)階段,裂紋貫通破壞階段;定量分析了應(yīng)變峰值、卸載剛度及損傷變量在循環(huán)荷載過程中的變化規(guī)律,單軸循環(huán)試驗(yàn)初始損傷階段的損傷程度較大,第3階段損傷變量變化顯著;三軸循環(huán)試驗(yàn)損傷過程中第1階段最顯著,而在損傷第3階段,煤樣臨近破壞時(shí)損傷變量略微升高,與單軸試驗(yàn)損傷變量顯著增加的情況不同;循環(huán)應(yīng)力上限處聲發(fā)射現(xiàn)象最強(qiáng)烈,說明循環(huán)過程中應(yīng)力上限時(shí)的內(nèi)部損傷程度最大。分級(jí)循環(huán)荷載試驗(yàn)結(jié)果顯示:分級(jí)荷載增加初期應(yīng)變回滯環(huán)較密集,聲發(fā)射現(xiàn)象顯著,試樣破壞時(shí)聲發(fā)射計(jì)數(shù)最大;各級(jí)循環(huán)也具有損傷不同階段特征,達(dá)到損傷穩(wěn)定階段的損傷變量近似值與均值壓力呈指數(shù)型變化關(guān)系。
[Abstract]:The coal samples were investigated by single axis and three axis mechanical strength test of conventional loading and cyclic loading conditions, using acoustic emission technique, uniaxial cyclic loading and three axial cyclic loading conditions of coal damage evolution and comparative analysis of system research. Conventional cyclic loading test results showed that: from the end to the initial cycle. The internal damage process of coal rock has 3 obvious stages, namely the initial damage stage, micro crack initiation and stable growth stage, crack failure stage; the quantitative analysis of the variation of peak strain, unloading stiffness and damage variable in the cyclic loading process, uniaxial cyclic tests of initial damage stage damage degree third stage of damage variables change significantly; three axis cycle test during the first stage of the most significant, and damage in the third stage, the coal sample near destruction damage variable is slightly higher, and the single axis test Check the damage variable significantly increased the different cyclic stress; the upper limit of the acoustic emission phenomenon is most intense, that cycle should be the upper limit of the damage degree of internal force. The maximum grade cyclic loading test results show that the classification of load increase initial strain hysteresis loops were intensive, significant acoustic emission phenomenon, the sample failure acoustic emission count the maximum; the levels of circulating injury also has different characteristics, to achieve stable stage of damage damage variable approximation is an exponential change and mean pressure.

【作者單位】： 中國科學(xué)院武漢巖土力學(xué)研究所巖土力學(xué)與工程國家重點(diǎn)實(shí)驗(yàn)室;山東大學(xué)巖土與結(jié)構(gòu)工程研究中心;
【基金】：國家自然科學(xué)基金杰出青年基金資助項(xiàng)目(51225902)
【分類號(hào)】：TD315
【正文快照】： 250061)地下工程硐室開挖卸載后,硐室圍巖附近產(chǎn)生2次應(yīng)力場(chǎng),切向主要表現(xiàn)為加載,而徑向表現(xiàn)為卸載。在煤礦開采過程中,采煤工作面綜合機(jī)械化施工時(shí),預(yù)留煤柱和工作面附近的煤會(huì)受到各種采動(dòng)應(yīng)力的反復(fù)作用,產(chǎn)生持續(xù)反復(fù)的損傷變形,降低其承載能力[1-4]。針對(duì)原煤進(jìn)行循環(huán)加卸

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