含节理黄土的微生物灌浆因素分析

Microbial grouting factors for loess with joints

在自行建立的含节理黄土微生物灌浆模型的基础上,通过有限元仿真软件COMSOL进行数值建模及求解,通过考虑初始脲酶活性、胶结液浓度、节理开度等因素,计算分析3种灌浆因素影响下的节理与孔隙的填充率以及黄土体的有效加固范围,对节理-黄土体的微生物灌浆加固效果进行研究。结果表明:初始脲酶活性是影响灌浆效果的重要因素;对于胶结液浓度,为同时考虑加固效果和减少废液量,应选用适宜的胶结液浓度;节理开度对加固深度的影响较明显,与节理水流入渗规律一致。综合分析3种灌浆因素发现,距灌浆口有限深度处的含节理黄土加固效果较好,灌浆均匀性有待提高。

On the basis of the established biogrout model for loess with joints,numerical modeling and solution are carried out by means of the finite element simulation software COMSOL.Considering the initial urease activity,cement concentration and joint aperture,the filling rates of joints and porosity aswellas the effective reinforced area of loess mass under three grouting factors are calculated and analyzed.The reinforcement effect of join-loess mass is studied.The results show that the initial urease activity is an important factor affecting the grouting effect.For the concentration of cement liquid,in order to consider the reinforcement effect and to reduce the amount of waste liquid at the same time,the appropriate concentration of cement liquid should be selected.The effect of joint aperture on the depth of reinforcement is more obvious,which is consistent with the law of water infiltration for the joints.The comprehensive analysis of the three grouting factors shows that the reinforced effect of loess with joints at a limited depth from the grouting port is better,and the grouting uniformity needs to be improved.