钢花管静压注浆在富水破碎带地层中的应用  

Application of Pressure Grouting Using Perforated Steel Pipe in Saturated and Fractured Zones

作　　者：姚燕飞 刘清华 黄旭华 赵立权 YAO Yanfei;LIU Qinghua;HUANG Xuhua;ZHAO Liquan(Modern Investment Co.Ltd.,Changsha 410000;China Railway Seventh Bureau Group Wuhan Engineering Co.Ltd.,Wuhan 4300003;Xiangtan University,Xiangtan 411100)

机构地区：[1]现代投资股份有限公司,长沙410000 [2]中铁七局集团武汉工程有限公司,武汉4300003 [3]湘潭大学,湖南湘潭411100

出　　处：《土工基础》2024年第4期623-626,634,共5页Soil Engineering and Foundation

摘　　要：富水破碎带地质条件下,下穿既有高铁的公路桥人工挖孔桩施工不但可能因岩土体破碎、强度低而引起桩壁垮塌失稳,影响高铁高架桥桩基,也可能因地下水位急剧下降,岩土固结而造成地层不均匀沉降,影响高铁运行。在方案综合比选的基础上,采用了钢花管静压注浆工艺:分别在人工挖孔桩砼护壁外侧300 mm、600 mm处采用梅花形布置注浆孔,采用水灰比0.7∶1浆液,掺入8%水玻璃、0.5%食盐掺量、0.1%三乙醇胺,注浆压力控制于0.5 MPa~0.8 MPa。现场实验及监测数据表明:岩土体孔隙率填充率提高了108.3~162.4%,透水率和渗透系数分别降低了80.1%、76.6%,施工过程未出现高铁及周边地面变形,保证了施工期间的高铁安全。Within the geological condition of the saturated and fracture zone,the construction of hand-dug piles for a highway bridge passing through the existing high-speed railway may not only adversely affect the piled foundation of a high-speed railway viaduct due to the collapse and instability of the hand-dug shaft caused by the broken and low strength of the bedrock and soils.This saturated and fractured zone might also affect the operation of the high-speed railway due to the differential ground settlement caused by the rapid drawdown of the groundwater level.Based on the comprehensive selection of the feasible mitigation methods,the static pressure grouting process by using the perforated steel pipe is adopted.Two circles of the pressure grouting are arranged in triangular spacing at 300 mm and 600 mm,respectively,on the perimeter of the concrete pipe wall of the hand-dug hole piles.The grouting slurry with water-cement ratio of 0.7:1 is used,mixed with 8%water glass,0.5%salt mixing,0.1%triethanolamine,and the pressure of the grouting is controlled to be 0.5 MPa~0.8 MPa.The on-site experiments,i.e.monitoring data show that:the filling rate of porosity of in the soil material has been increased by 108.3~162.4%.The coefficient of permeability has been reduced by 80.1%and 76.6%,respectively.No deformation of high-speed rail and the surrounding ground was observed in the construction process,which ensures the safety of high-speed rail during the construction period.

关 键 词：富水破碎地层 钢花管静压注浆 止水 加固 

分 类 号：TU472[建筑科学—结构工程]