地下工程富水软弱地层注浆加固理论研究新进展

Newprogress in grouting reinforcement theory of water-rich soft stratum in underground engineering

目前我国已成为世界公认的隧道与地下工程建设规模和难度最大的国家,断层破碎带、富水砂层等富水软弱地层已经成为地下工程修建过程中最为常见的不良地质体,注浆是治理富水软弱地层的主要方法。结合本课题组研究特色,介绍本课题组在富水软弱地层注浆加固理论、模拟试验及注浆控制方法等方面的最新研究进展。注浆加固理论方面,考虑劈裂注浆加固体的分层特征与空间衰减特征,综合注浆加固后浆脉、被压密地层及原状地层的性能参数及空间展布形态,建立劈裂注浆加固效果定量计算方法;考虑砂层渗透注浆过程中渗滤效应所造成的水泥颗粒滞留空间不均匀性,针对平面径向流渗透注浆形式建立注浆加固体强度的定量计算公式,揭示注浆加固强度的空间衰减特征。注浆加固模拟试验方面,研发隧道突水突泥灾后注浆模拟试验系统,总结突泥塌腔及软弱破碎区域优先充填扩散规律和封闭空间加固区域内多序次劈裂注浆扩散规律;研发可视化劈裂注浆模拟试验系统,揭示注浆过程中劈裂通道形态随时间变化规律,获得试验条件下的劈裂-压密注浆影响范围。注浆控制方法方面,针对泥质断层破碎带及富水砂层分别提出针对性的注浆控制方法,可为富水软弱地层注浆工程实践提供有效指导。

At present,China is the country with the greatest scale and difficulty in the construction of tunnels and underground projects.Fault fracture zone,water-rich sand strata and other water-rich soft strata have become the most common unfavorable geologic bodies in the construction of underground engineering.Grouting is the main method to treat water-rich soft strata.Based on the characteristics of the project team,the latest research progress in grouting reinforcement theory,simulation test and grouting control method in water-rich soft strata was introduced.In terms of grouting reinforcement theory,considering the layered characteristics and space attenuation characteristics of reinforced soil,a quantitative method for calculating the reinforcement effect of splitting grouting was established by synthesizing the performance parameters and spatial distribution of grouting veins,compacted strata and undisturbed strata.Whats more,considering the inhomogeneity of the retention space of cement particles caused by filtration effect in sand layer,a quantitative strength calculation method of grouting reinforced composition ground was established for the permeation grouting form of plane radial flow.On this basis,the spatial attenuation characteristics of grouting strength were revealed.In the aspect of simulation test of grouting reinforcement,a simulation test system for grouting after water inrush and mud inrush of tunnel was developed.The rule of priority filling and diffusion in cavities and soft broken areas and the lawof multi-sequence split grouting diffusion in closed space strengthened area were summarized.A visual simulation test system for splitting grouting was developed,which could reveal the variation rule of split channel shape with time during grouting.The influence range of splitting and compaction grouting under test conditions was obtained.In terms of grouting control methods,the corresponding grouting control methods for muddy fault fracture zone and water-rich sand layer were put forward respectively,which could provide effective guidance for grouting engineering practice in water-rich weak stratum.