煤矿沉陷区土地的复垦与建筑利用

Shaft sinking with concrete curtains

矿井开采引起地面下沉与变形,在大多数情况下,它会对地面土地、水系及各类建筑物、构筑物造成不同程度的影响。为了减少上述采动引起的地面破坏程度以及合理利用受采动影响的地面土地,许多国家都在进行这方面的研究和试验工作,并且在沉陷区土地的复垦及建筑利用方面取得了许多有实际效益的成果和经验。

22 vertical shafts and 2 inclined shafts have been developed by using this technology and practice shows that this technology is one of the effective special shaft sinking methods. The curtain in the main shaft of Liang Jia is 50 m deep with its centre of 8.35m. Slot holes were drilled by drills. Rotary drills were used to drill main holes while percussion drlls to cut auxiliary holes,forming a new technique- 'first to pilot then to expand, two times drilling and one time cutting'. The slot holes were divided into 3 sections.Their drilling was carried out using mud for wall protection and mud-debris discharge system was used.After each section of slot holes had been done, hole bottom was cleaned and mud was changed. Tubes were put into holes for pouring concrete under mud. concrete was mixed on the surface and then put into slot holes by truck-elevators. Concrete flowed down the slot holes through two sets of pilot tubes. The pilot tubes were burried into 1.5-6 m all the time and pulled up while pouring. Slot holes were connected together by rigid connecting tubes.As the concrete was poured up and set, connecting tubes were slowly lifted, forming connecting holes.The best time to lift the connecting tubes is 1.1 times of the initial setting of the concrete.Model experiment and on-site observation show that the stress of the concrete curtains does not change much after shaft sinking process that indicates that the strength of the curtains structure is a little bit too high. Therefore, design theory and calculation method should be further improved.