大型水利工程隧洞进口深基坑支护型式研究

Research on the support type of deep foundation pit at the entrance of large water conservancy tunnel

研究大型水利工程隧洞进口深基坑支护型式,从而提供深基坑支护的新方法,进一步拓宽深基坑支护的应用范围。通过水泥土桩、地下连续墙、咬合桩等深基坑几种支护型式技术可行性、可持续发展、经济合理等比较,并结合深基坑支护稳定计算复核支护型式安全性。咬合桩防水性能较好,整体刚度较大,深基坑变形小,确保了较差地质大型水利工程隧洞进口边坡开挖安全,为隧洞顺利地开挖和运行创造安全条件;在大断面隧洞进口位置采用咬合桩支护,占用空间较小,有效解决了征地及拆迁困难难题,干孔作业,容易成孔,施工速度快,为按期施工完成创造条件;咬合桩桩工程造价低,无须排放泥浆,机械设备振动少、噪声低。与其他深基坑支护型式相比,咬合桩具有较高经济、安全、环保性,其有效增强了咬合桩的应用范围,为设计提供新方法。

Research on the types of deep foundation pit support for large water conservancy engineering tunnels,in order to provide new methods for deep foundation pit support and further expand the application scope of deep foundation pit support.By comparing the technical feasibility,sustainable development,and economic rationality of several types of support for deep foundation pits,such as cement soil piles,underground continuous walls,and interlocking piles,and combining with the stability calculation of deep foundation pit support,the safety of the support types is reviewed.The interlocking pile has good waterproof performance,high overall stiffness,and small deformation in deep foundation pits,ensuring the safety of excavation of the entrance slope of large water conservancy tunnels with poor geological conditions,and creating safe conditions for the smooth excavation and operation of tunnels;Adopting bite pile support at the entrance of the large cross-section tunnel takes up less space,effectively solving the difficulties of land acquisition and demolition.Dry hole operation makes it easy to form holes,and the construction speed is faster,creating conditions for timely completion of construction;The construction cost of bite pile is low,there is no need to discharge mud,and the mechanical equipment has less vibration and low noise.Compared with deep foundation pit support types,interlocking piles have higher economic,safety,and environmental friendliness,effectively enhancing the application range of interlocking piles and providing new methods for design.