陕北冻土高水位流沙地段管沟开挖方法研究

高水位流沙地段的管沟开挖一直是施工过程中的难点,虽然目前可采用深井抽排降水法、密闭管抽水降水法、明渠抽排降水法、木桩固定沟壁加抽水降水法等方法,但施工工序繁琐,成本高。文中提出应用冻土原理,在一次双侧沉管的基础上,采用二次双侧开挖新方法,将地下高水位的挖沟不利条件变为有利条件,降低了土方开挖量,取消了抽排水措施,提高了施工工效,节约了施工成本。该方法在陕京三线设计1标段榆阳马家峁段AA001-AA005高水位流沙地段工程施工中取得了良好的施工工效与经济效益。

Research on the Method for Trench Excavation of Frozen Soil and High Water Level and Quicksand Section in Northern Shaanxi

The pipe drain excavation is a difficult problem during the construction process in a high-water level and quicksand section.Though in a high-water level and quicksand section,trench excavation methods include the deep well pumping method,the sealed tube pumping,the open channel drainage precipitation method,the stakes fixed groove precipitation method and the plus pumping wall method.Thus the construction process is complicated and costs are high.By applying the principle of frozen soil,based on bilateral immersion,the new method of secondary sides digging is used.The method can change adversity of the underground water level into favorable conditions,reducing the amount of earth excavation,canceling the drainage and pumping measures,improving the construction efficiency,and also saving construction costs during the trench excavation.The method has achieved a good construction efficiency and economic result in the construction of the high water level and quicksand section in the Yangma hilly area of AA001-AA005 on the third Shaanxi-Beiing pipeline designed as Section 1.