全强风化砂页岩地层压密加固效果试验

Experimental on the Grouting Compacting Effect in the Total Strongly Weathered Sand Shale Stratum

全强风化砂页岩地层注浆加固工程中常常伴随着地层压密现象,压密加固后地层的物理力学性能得到显著提升。为了研究全强风化砂页岩地层的注浆压密效果,以压缩模量、黏聚力、内摩擦角、渗透系数作为表征地层物理力学性能的主要指标,通过开展室内试验,获得了不同注浆压力与含水率条件下地层力学性能的提升规律,建立了可定量化描述不同含水率条件下注浆压力与地层物理力学参数的关系模型。研究结果表明:通过提高注浆压力可显著提高全强风化砂页岩地层压缩模量,高注浆压力作用下,地层压缩模量最大增长近10倍。当注浆压力处于较低水平时,加固后地层黏聚力的提升受含水率和注浆压力影响明显。当注浆压力处于较高水平时,加固后不同含水率情况下地层土体黏聚力基本趋于一致,地层黏聚力的提升不再受含水率的影响。地层内摩擦角在注浆压密后的提升程度始终受自身含水率的影响。注浆压力的提升可进一步提高地层的抗渗能力。采用建立的注浆压力-地层物理力学参数关系模型对某工程实例进行计算分析,给出了满足地层加固要求的注浆压力设计值,注浆治理后开挖揭露浆脉清晰、地层稳定,所提出的模型可为全强风化砂页岩地层注浆治理参数设计提供参考。

Grouting project in total strongly weathered sand shale(TSWSS)is usually accompanied by phenomenon of stratum compression.After grouting operation,the physical mechanical properties of the stratum have been significantly improved.To investigate grouting compression in TSWSS,the compression modulus,cohesion,internal friction angle and permeability coefficient were selected as the main typical parameters of stratum properties.The influence of grouting pressure on the improvement of stratum properties was obtained through experiment.The quantitative relationships between the grouting pressure and stratum properties under the different moisture content were established.The research results show that the compression modulus of TSWSS can effectively improve by increasing the grouting pressure.The compression modulus has increased by nearly 10 times with a higher grouting pressure.When the grouting pressure is at a low level,the improvement in cohesion and internal friction angle was influenced by moisture content and grouting pressure.When the grouting pressure is at a high level,the improvement in cohesion was not controlled by moisture content.The improvement in internal friction angle was always influenced by moisture content.The incensement in grouting pressure can further improve anti-seepage capacity of the stratum.The relationship model was used to verified by engineering example.The design parameter of grouting pressure that meet the requirements of stratum reinforcement was proposed.After grouting,the exposed grouting veins were clear and the stratum was stable.The proposed model can provide guidance for the design of grouting treatment parameters in TSWSS.