富水砂层高效注浆材料试验与应用研究

Performance and engineering application of effective microfine cement-based grout(EMCG) for water-rich sand strata

以硅酸盐水泥熟料与工业废渣为原材,通过粒径分布优化、活性激发等优化方法,制备新型高效超细水泥基注浆材料(EMCG)。通过室内试验,研究EMCG材料的流动性能、黏度、析水稳定性、初终凝、强度、体积稳定性等主要性能,对比分析普硅42.5水泥(OPC)、超细硅酸盐水泥(MC)、超细硫铝酸盐水泥(MSAC)及EMCG主要性能;基于XRD及SEM矿物测试,分析EMCG水化机制;通过注浆加固模拟试验,研究EMCG对富水砂层的注浆加固性能,对比分析不同注浆材料浆–岩微观加固模式;通过现场试验,研究EMCG对富水砂层封堵加固效果。研究结果表明:水灰比1.5∶1~2∶1、粉煤灰40%~50%、超塑化剂1.5%~2.0%时,浆液扩散性能最优;浆液稳定状态主控因素为材料细度与水灰比;EMCG材料强度及加固效果最优,MSAC,MC次之,OPC最差;EMCG 7 d加固体强度超过28 d强度70%;EMCG具有砂层扩散性好、泵送稳定、凝胶时间可控、体积稳定、水化活性高、高强、矿物合理、结构致密等优点;EMCG有效提高了富水砂层地层整体性与稳定性,具有显著性能优势与较好工程适用性,是一种比较好的用于地下工程富水砂层加固的注浆材料。

The Portland cement clinker and industrial wastes were selected to prepare the effective microfine cement-based grout(EMCG)adopting optimization methods of particle size distribution and hydration activity excitation.Through laboratory tests,the main features of EMCG such as flowability,viscosity,stability,initial/final setting time,strength and volume stability were studied,and the main properties of ordinary Portland cement 42.5(OPC),microfine Portland cement(MC),microfine sulphoaluminate cement(MSAC)and selfdeveloped EMCG were compared.Based on mineral test methods of XRD and SEM,the hydration mechanism of EMCG was studied.Through grouting simulation experiments,the grouting strengthening property of EMCG on sand specimens was investigated,and different microcosmic reinforcement modes of slurry-rock for various grouts were compared.Field tests were performed to evaluate the plugging and reinforcement effects of EMCG on water-rich sand strata.The results show that the flowability of EMCG suspension is optimal when the water solid ratio(W/S),and the amounts of fly ash and superplasticizer(SP)are 1.5∶1–2∶1,40%–50%and 1.5%–2.0%respectively and that the controlling factors of pumping stability are fineness and W/S.The strength and reinforcement effect of EMCG are the best,followed by MSAC and MC,and then OPC.The 7-day strengths of EMCG reinforced specimens are over 70%of the 28-day strengths.It is also shown that the EMCG suspensions have advantages of excellent groutability,pumping stability,setting controllability,volume stability,high strength,favorable hydration mineral,compact microstructure and so on,and hence,can effectively improve the integrity and stability of water-rich sand strata.Due to its high performance and excellent engineering applicability,EMCG is an efficient and excellent grout especially for anti-seepage and reinforcement of water-rich sand strata.