CAJ | 학술논문

岩石材料的宏观力学特性与其内部细观结构演化有十分密切的关系，对典型难溶盐岩钙芒硝在盐溶液溶浸环境下力学特性弱化和细观结构演化进行研究，初步揭示其力学特性弱化的细观机制。研究发现：在盐溶液溶浸作用下，由于矿体胶结物中亲水性矿物吸水膨胀崩解、钙芒硝中硫酸盐的溶解、化学反应离子交换、氯离子侵蚀损伤等因素的作用，钙芒硝孔隙率随“溶液浓度”和时间的变化而非线性演化，从而导致力学特性严重弱化。在盐溶液中溶浸20 d，钙芒硝强度弱化系数低至0.1～0.2。由于钙芒硝矿体内泥质胶结成分的水理水化作用，泥质部分膨胀或崩解，钙芒硝矿体变形表现出应变软化与韧性破坏特征。细观结构演化结果表明，盐溶液溶浸作用下，难溶钙芒硝孔、裂隙演化缓慢，但在淡水溶液中孔隙演化速度是半饱和与饱和溶液中的数倍甚至数百倍。淡水中溶浸48 h后孔隙率高达16.62%，是原始状态孔隙率的9倍；半饱和盐溶液溶浸48 h后，孔隙率是原始状态的3倍，而饱和溶液溶浸48 h后，孔隙率增幅仅为2.8%。孔隙率变化主要是由于钙芒硝矿体中硫酸盐的溶解和结晶，胶结物成分(主要为伊利石、蒙脱石)的水理、膨胀，这也是钙芒硝力学特性弱化的根本原因。本研究对深入认识可溶岩(包括钙芒硝)物理力学特性弱化，并指导盐类矿床原位溶浸开采及层状盐岩溶腔油气储库建造等相关工程实践，具有重要理论意义与应用价值。
암석재료적굉관역학특성여기내부세관결구연화유십분밀절적관계，대전형난용염암개망초재염용액용침배경하역학특성약화화세관결구연화진행연구，초보게시기역학특성약화적세관궤제。연구발현：재염용액용침작용하，유우광체효결물중친수성광물흡수팽창붕해、개망초중류산염적용해、화학반응리자교환、록리자침식손상등인소적작용，개망초공극솔수“용액농도”화시간적변화이비선성연화，종이도치역학특성엄중약화。재염용액중용침20 d，개망초강도약화계수저지0.1～0.2。유우개망초광체내니질효결성분적수리수화작용，니질부분팽창혹붕해，개망초광체변형표현출응변연화여인성파배특정。세관결구연화결과표명，염용액용침작용하，난용개망초공、렬극연화완만，단재담수용액중공극연화속도시반포화여포화용액중적수배심지수백배。담수중용침48 h후공극솔고체16.62%，시원시상태공극솔적9배；반포화염용액용침48 h후，공극솔시원시상태적3배，이포화용액용침48 h후，공극솔증폭부위2.8%。공극솔변화주요시유우개망초광체중류산염적용해화결정，효결물성분(주요위이리석、몽탈석)적수리、팽창，저야시개망초역학특성약화적근본원인。본연구대심입인식가용암(포괄개망초)물리역학특성약화，병지도염류광상원위용침개채급층상염암용강유기저고건조등상관공정실천，구유중요이론의의여응용개치。
The internal meso-structure development of rock material contributes a lot to its macroscopic mechanical properties. The mechanical properties weakening mechanism and internal meso-structure development of typical glauberite soaked in brine are studied;and the mechanism of mechanical properties weakening is revealed. It is found that under the actions of swelling and disintegration of hydrophilic mineral in the cement of the rock,the dissolution of sulfate,the ion exchange and the chloride ion erosion damage,etc.,the porosity of glauberite soaked in brine is changed nonlinearly with the solution concentration and soaking time. So,the mechanical properties weakens. The strength weakening coefficient decreases to 0.1-0.2 after the glauberite being soaked in brine for 20 d. Because of the water effect and hydration,the argillaceous content contained in the glauberite would swell or disintegrate. So the deformation of glauberite shows the characteristics of strain softening and ductile from the original brittle behavior. The meso-structure development results also show that the pores in glauberite soaked in brine develop more slowly than that in pure water. The pores development rate in fresh water is several to hundreds of times as that in brine. The porosity of glauberite soaked in water for 48h increases to 16.62%,which is 9 times of that of natural state. And the porosity of glauberite soaked in half saturated solution for 48 h is 3 times of its natural state. However,the porosity of glauberite soaked in saturated solution for the same time has an increase of only 2.8%. The change of porosity is mainly due to dissolution and hydration of sulfate in the glaubetire,the water effect and cement of hydrophilic minerals(mainly glimmerton and smectite contents) swelling. These are definite reasons for the mechanical property weakening of the glauberite. The research results are significant either for study of physico-mechanical properties of the glauberite or for in situ leaching mining of salt deposits and salt cavern construction for oil and gas storage and other related engineering practice.