软岩冻结凿井井帮稳定性影响因素敏感性分析

西安科技大学 建筑与土木工程学院,陕西 西安 710054

软岩冻结凿井; 正交模拟试验; 敏感性分析; 数值模拟

Sensitivity analysis of influential factors of surrounding rock stability in soft rock freezing sinking
WANG Lei,CHEN Shi-guan,LI Zu-yong

(College of Civil and Architectural Engineering,Xi'an University of Science and Technology,Xi'an 710054,China)

freezing sinking in soft rock; orthogonal simulation test; sensitivity analysis; numerical simulation

DOI: 10.13800/j.cnki.xakjdxxb.2018.0112

备注

西部软岩冻结凿井施工设计主要参照中东部冻结凿井施工经验,造成掘砌段高、冻结强度等关键参数设计无可靠依据。为此,通过对冻结软岩围岩径向变形主要影响因素进行辨识,并充分考虑影响因素之间的内在关联性和实际工程状况,根据正交试验理论设计了4因素4水平正交试验方案; 根据中砂岩强度参数与冻结温度的相关性,通过fish编程对数值模型进行参数赋值; 经过模拟分析,确定最大径向位移点出现在2.13h/3处,采用2h/3处径向位移为评价指标,经极差分析,掘砌段高对径向变形影响最大,且段高超过4.0 m后影响显著,最后经补充实验方案模拟分析,结果表明,掘砌段高影响最大,为22.7%,而冻结强度为-24.0 ℃时,增加冻结强度对控制冻结变形并不明显。分析结论对冻结凿井施工中冻结温度的确定和掘砌段高设置具有重要应用价值。

The construction design of freezing sinking in western soft rock mainly refers to the construction experience of freezing sinking in East Midlands,which the determination of key parameters has no reliable evidence such as the section height of excavation,freezing strength,etc.For this purpose,through the identification of the main factors which influence the freezing soft rock radial deformation of surrounding rock and fully considering the intrinsic relationship between influential factors and the actual engineering situation,four factors and four levels orthogonal test scheme were designed according to the theory of orthogonal test.Based on the correlation ofsandstone strength parameters andfreezing temperature,and programmed with fish parameter assignment for numerical model,the maximum radial displacement points is actually appeared at 2.13 h/3.Using 2 h/3 radial displacement as the evaluation index,the section height of excavation has the biggest effect on the radial deformation by range analysis,and it has significant affect after more than 4.0 m.Finally,after supplement program simulation analysis,the results show that the section height has the largest impact with 22.7%.When the freeze strength is 24.0 ℃,the increase of freeze strength to control the deformation of frozen is not obvious.The conclusion has a practical reference for the determination of freezing temperature in the freezing sinking construction and setup of the section height of excavation.