The invention provides a radial pre-grouting method before excavation of lower steps in confined water stratum tunnel, including S1: after completion of initial support for upper steps excavation, a step grouting hole is opened, the seepage point of initial support is first drained by grouting pipe, then a step radial grouting is carried out on upper steps, the thickness of consolidation ring of upper steps is 3 5m; and the arrangement of radial grouting holes and grouting technology of upper steps are based on seepage point position. Setting, characteristics, seepage volume and water pressure determination. S2: Radial pre-grouting of the lower step is carried out on the surrounding rock of the lower step 2 m away from the face of the face, and the thickness of the consolidation ring of the lower step is 7 10 m. According to the direction of the upper step seepage point and the structural plane, the seepage direction of the fracture water and the outlet point of the lower step are inferred, and the pre-grouting holes of the lower step are arranged accordingly. The number of pre-grouting holes is determined according to the seepage amount of the seepage point associated with the upper step. The invention reduces the difficulty of radial grouting after excavation of lower steps, speeds up the secondary grouting speed and improves the grouting effect.
【技术实现步骤摘要】
承压水地层隧道下台阶开挖前径向预注浆方法
本专利技术属于隧道及地下工程
,具体地说,涉及承压水地层隧道下台阶开挖前径向预注浆方法。
技术介绍
承压水地层隧道径向注浆堵水在围岩开挖后进行,当采用台阶法施工,在上台阶开挖后既完成上台阶径向注浆施工,对上台阶围岩渗漏点进行注浆封堵;下台阶开挖后再对下台阶渗漏点进行径向注浆堵水,与上台阶径向注浆堵水相比较,下台阶围岩渗水压力增大,增加了径向注浆难度,且难以保证注浆效果。
技术实现思路
针对现有技术中上述的不足,本专利技术的目的在于提供一种承压水地层隧道下台阶开挖前径向预注浆方法。为了达到上述目的,本专利技术采用的解决方案是:承压水地层隧道下台阶开挖前径向预注浆方法,包括:S1:上台阶开挖完成初期支护后,开上台阶注浆孔,初期支护渗漏点用注浆管先引流,然后利用注浆管对上台阶进行上台阶径向注浆,上台阶固结圈厚度为3-5m;上台阶径向注浆孔布置与注浆工艺根据渗漏点位置、特性、渗水量、水压确定。S2:利用注浆管对距掌子面2m以外的下台阶的围岩进行下台阶径向预注浆,下台阶固结圈厚度为7-10m;根据上台阶渗漏点裂隙及构造面走向,推断裂隙水渗流方向及下台阶出水点,据此布置下台阶预注浆孔;预注浆孔数量根据与上台阶相关联的渗漏点渗水量确定,高压大流量渗漏点,需要在附近增设引流减压孔。本专利技术的有益效果是:采用台阶法施工,在上台阶开挖后即完成上台阶径向注浆施工,对上台阶围岩渗漏点进行注浆封堵,然后进行下台阶径向预注浆施工,对下台阶围岩渗漏点进行注浆封堵,使下台阶开挖后渗漏点、渗水量减少,渗水压力降低。降低了下台阶开挖后再次进行径向 ...
【技术保护点】
1.承压水地层隧道下台阶开挖前径向预注浆方法,其特征在于,包括:S1:上台阶开挖完成初期支护后,开上台阶注浆孔,初期支护渗漏点用注浆管先引流,然后利用注浆管对上台阶进行上台阶径向注浆,上台阶固结圈厚度为3‑5m;上台阶径向注浆孔布置与注浆工艺根据渗漏点位置、特性、渗水量、水压确定;S2:利用注浆管对距掌子面2m以外的下台阶的围岩进行下台阶径向预注浆,下台阶固结圈厚度为7‑10m;根据上台阶渗漏点裂隙及构造面走向,推断裂隙水渗流方向及下台阶出水点,据此布置下台阶预注浆孔;预注浆孔数量根据与上台阶相关联的渗漏点渗水量确定,高压大流量渗漏点,需要在附近增设引流减压孔。
【技术特征摘要】
1.承压水地层隧道下台阶开挖前径向预注浆方法,其特征在于,包括:S1:上台阶开挖完成初期支护后,开上台阶注浆孔,初期支护渗漏点用注浆管先引流,然后利用注浆管对上台阶进行上台阶径向注浆,上台阶固结圈厚度为3-5m;上台阶径向注浆孔布置与注浆工艺根据渗漏点位置、特性、渗水量、水压确定;S2:利用注浆管对距掌子面2m以外的下台阶的围岩进行下台阶径向预注浆,下台阶固结圈厚度为7-10m;根据上台阶渗漏点裂隙及构造面走向,推断裂隙水渗流方向及下台阶出水点,据此布置下台阶预注浆孔;预注浆孔数量根据与上台阶相关联的渗漏点渗水量确定,高压大流量渗漏点,需要在附近增设引流减压孔。2.如权利要求1所述的承压水地层隧道下台阶开挖前径向预注浆方法,其特征在于,上台阶径向注浆和下台阶径向预注浆注均采用分段式,首段注浆压力采用1MPa,第二段注浆压力采用1.5MPa~2MPa。3.如权利要求1所述的承压水地层隧道下台阶开挖前径向预注浆方法,其特征在于,上台阶径向注浆采用双液浆,下台阶采用纯水泥浆。4.如权利要求3所述的承压水地层隧道下台阶开挖前径向预注浆方法,其特征在于,纯水泥浆的水灰比采用2:1、1:1、0....
【专利技术属性】
技术研发人员:杨文富,沙宗天,刘凯,陈通,廖乙宇,李强,吕德斌,彭唯泽,
申请(专利权)人:中铁二局第二工程有限公司,
类型:发明
国别省市:四川,51
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