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厚表土井筒修复内套钢板混凝土井壁技术研究

Study on the technology of inner steel plate concreteshaft lining for thick topsoil wellbore repair

  • 摘要: 为解决由突水溃砂引起的厚表土地层井筒破损问题,针对其竖向压裂、法兰盘拉开及井筒偏斜等破坏特征,提出钢筋混凝土井壁与内套钢板(钢纤维)混凝土井壁结构相结合的全深套壁修复加固方案。以淮南矿区某在建煤矿副井为工程背景,结合现场井壁破坏形式及突水溃砂机理,提出井筒套壁设计原则和结构形式;根据现场井筒变形情况和相关规范计算得出套壁厚度以及钢板、混凝土应力;通过分析计算结果并结合现场实际,制定套壁施工方案;采用振弦传感器法对修复后内套井壁壁间压力、环向钢筋应力和变形进行监测,并长期观测检查孔水位。研究结果表明:①按组合筒公式计算得出,内套钢板(钢纤维)混凝土复合井壁结构钢板应力范围为187.6~292.0 MPa,混凝土应力范围为32.8~51.0 MPa,均满足设计要求;②施工完成后,壁间压力和环向钢筋应力监测最大值分别为3.2 MPa和113.4 MPa,均处于安全范围内;③修复后井筒涌水量约为4 m3/d,内套钢板混凝土复合井壁结构防水效果突出,井筒结构安全稳定;④在累深315.0~567.7 m段,井筒多处破损,以偏斜破坏为主,最大偏斜值达1 154 mm,在严重偏斜段,沿竖向采用分模、随偏、微调方式施工内套井壁,解决各模钢板接茬过渡施工难点。该方案利用单层内钢板(钢纤维)混凝土复合井壁结构其自身强度高、防水性能好等优点,不仅大幅减少内套井壁厚度,且保证修复后井筒的安全稳定运行。

     

    Abstract: In order to solve the damage question of shaft in thick topsoil caused by water inrush and sand burst, in view of its failure characteristics such as vertical fracturing, flange opening and wellbore deflection, adopting the repair and reinforcement scheme of full deep casing wall, which combines reinforced concrete shaft wall with inner sleeve steel plate (steel fiber) concrete shaft wall structure.Taking auxiliary shaft of a coal mine under construction in huainan mining area as the engineering background, combining with the failure form of wellbore and the mechanism of water inrush and sand burst, the design principle and structure form of wellbore sleeve are put forward; the thickness of sleeve wall and the stress of steel plate and concrete are calculated according to the deformation of wellbore in situ and relevant codes; by analyzing the calculation results and combining with the actual situation in the field, the sleeve wall construction scheme is formulated; vibration string sensor method is used to monitor the wall pressure, circumferential reinforcement stress and deformation of the repaired inner sleeve, and observing the water level of the inspection hole for a long time.The results show that,①according to the formula of composite tube, the stress range of steel plate (steel fiber) concrete composite shaft lining structure steel plate is 187.6~ 292.0 MPa, and that of concrete is 32.8~ 51.0 MPa, which all meet the design requirements;② after completion of construction, the maximum monitoring values of wall pressure and circumferential reinforcement stress are 3.2 MPa and 113.4 MPa respectively, which are within the safe range;③after repairing, the wellbore water inflow is about 4 m3/d, the waterproof effect of the inner steel plate concrete composite wellbore structure is outstanding, and the wellbore structure is safe and stable;④ in the 315.0~567.7 m deep section, the borehole is damaged in many places, mainly by deflection, the maximum deflection value is 1 154 mm, in the severe deflection section, the inner sleeve wall is constructed vertically by mode division, deflection following and fine-tuning, so as to solve the difficulties of the transition construction of each model steel plate stubble connection.The scheme utilizes the advantages of single-layer inner steel plate (steel fiber) concrete composite shaft lining structure, such as high strength and good waterproofing performance, not only greatly reduces the thickness of inner sleeve shaft lining, but also ensures the safe and stable operation of repaired shaft lining.

     

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