深部矿井回风井冻结施工过程中管涌事故分析
Analysis on water and soil gushing accident occurred in deep mine air returning shaft during freezing construction
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摘要: 为了探讨冻结法井筒施工发生管涌事故的原因,以平煤一矿北三回风井为例,在混凝土井壁出现大量不规则而且宽度和深度较大的裂缝后,结合现场测试数据、地质条件和施工工艺对管涌事故进行了综合分析。由分析结果可知,管涌事故的主要原因为:1施工工艺不合理,如冻结管孔偏斜较大,注浆压力过大,混凝土浇筑不连续而出现施工冷缝,爆破装药量过大而引起的震动,致使混凝土在终凝前后就已产生载荷型裂缝;2混凝土配比、生产与养护不合理,如混凝土没有达到实际设计强度等级,无生产、浇筑养护措施,从而无法避免大体积混凝土的质量通病,即收缩裂缝;3地质条件的限制,如事故段岩石破碎,高角度裂隙发育,裂隙承压水压力大,构造应力大;同时,裂隙承压水与井壁外侧呈点接触或线接触,从而造成应力集中,发生横截面失稳现象。Abstract: in order to discuss the causes of water and soil gushing accident occured in a ground frezing construction of a mine shaft.based on the Norh No. 3 AirReturning Shaf of Pingmei No.1 Mine a er large abnormal and large with and depth cracks were appeared on the mine concrete lnr n comtbinaton with the site neasured data geological onditions and construction technology,a comprehensive analysis was conducted on the wa1er and soil gushing a ident .The analysis resuts showed that the major causes of the water and sall gushing accident were 1 the construcion fechnology was irationa.such as the rezing pipe borehole was too delecton.the grouting prssure was too igh.the concrete pouring was not continuous and the constrution cold joits ocured, overchaging of the exphosive lcaded caused lbration and theconcrete before and afer the fial sting would cause theloading cracks 2 the concrete mixing rato.,producton and curing were rational such as the .oncrete coud notreach the actal designed strength grade and no production and curing measures conducted,therefore lage area concrete qualt could notreach thedesigned requiremens.such the shrimkage crack 3 thelimitation of the geological co diton,he roce at the accident secion was broken,the igh angle cacks were develope.the crack pressurized water pressure was too high and the structural stress was too high .Mfeanwie the crack rssurzed water were in apoint comnection or inalinear connection with the outside of the mine sheaft and thus stress concentration occurred and the stablity lost of the cross-section was occurred.