考虑脆性损伤和水力耦合影响的立井井壁临界突水水压理论解

Theoretical solutions to critical water inrush pressure in vertical shaft lining under the influence of brittle damage and hydraulic coupling

针对混凝土这种准脆性材料的损伤特性引入脆性损伤因子,导出三轴状态下损伤变量表达式。采用脆性材料弹塑性损伤力学模型和轴压水压耦合作用下混凝土强度准则,基于水力耦合理论导出井壁承受的地下水压解析解,开展临界突水水压理论分析。结果表明高强混凝土承受的地下水压远高于普通混凝土,且随着混凝土强度提高井壁承受的水压越大,水压与损伤半径的曲线斜率增速越快。混凝土井壁承受的临界突水水压及临界损伤半径随着孔隙率增大明显降低,且混凝土强度越高降低速率越快,考虑水力耦合作用对井壁承受的临界突水水压影响很大。高强混凝土脆性损伤因子提高,临界突水水压随之降低。实例验证表明本文得到的理论解合理。

In view of the damage characteristics of quasi-brittle material in concrete,brittle damage factor is introduced,and the damage variable expression under triaxial state is deduced. Through elasto-plastic damage mechanics model of brittle materials and concrete strength criterion under axial compression and hydraulic pressure,based on the hydraulic coupling theory,analytical solution of groundwater pressure under shaft lining is obtained to theoretically analyze the critical water inrush pressure. Results have shown that groundwater pressure of high strength concrete is much higher than that of ordinary concrete. With the increase of concrete strength,the groundwater pressure increases and the slope of the curve between groundwater pressure and damage radius increases at a faster rate. The critical water inrush pressure and critical damage radius of concrete shaft lining obviously reduce with the increase of porosity, and the rate of decrease is faster as the strength of concrete increases, the hydraulic coupling having a great influence on the critical water inrush pressure on the shaft lining. The brittleness damage factor of high strength concrete increases and the critical water inrush pressure decreases obviously. The example verifies the rationality of the theoretical solution obtained in this paper.