CO2-ECBM中气固作用对煤体应力和强度的影响分析

基于固体表面能下降是引起固体膨胀的动力源的理论，给出了煤体吸附CH4和CO2后的膨胀应力的计算公式，对CO2和CH4吸附引起的膨胀进行了计算和分析，为评估CO2注入煤层后吸附引起的膨胀对煤层力学稳定性的影响提供了理论依据。取Griffith断裂理论中临界应力为煤体强度指标，给出了煤体吸附气体后强度下降的计算公式，对煤体自由膨胀条件下吸附CH4和CO2强度降低的情况进行了对比分析。

Preliminary theoretical study on impact on coal caused by interactions between CO2 and coal

Regarding the solid surface energy decrease as a result of adsorption of gas as the reason why the solid skeleton swells. A theoretical formula is given to estimate the swelling stress without displacement constraint, which is an appropriate assumption as the initial underground stress is so large. The swelling stresses caused by CO2 and CH4 respectively are compared. This is helpful in evaluating the mechanical stability in CO2-ECBM. Then another formula is given to evaluate the coal strength decrease caused by the CH4 or CO2 adsorption; the formula is helpful in evaluating the mechanical properties change and the mechanical stability after the adsorption of gases in CO2-ECBM.