VSM沉井下沉过程井壁受力规律研究

Variation of shaft wall force during the sinking of VSM caisson

为了研究VSM沉井井壁受力变化规律,结合施工工艺特点对VSM沉井的下沉过程及受力特性进行了分析。首先,依据VSM沉井下沉特点对其施工过程中所受荷载进行梳理,同时划分了沉井一个下沉循环中的典型运动状态;之后以G. G. Meyerhoff公式和规范为基础,对沉井下沉阻力进行分析计算,提出了考虑井内淹水的刃脚端阻力计算公式,并建立了井壁典型状态施工力学模型;最后,以矿山竖井工程为算例计算得出沉井几何参数、下沉阻力、下沉深度以及悬吊力之间的关系。结果表明:VSM沉井悬吊力大小随着下沉深度的增加并不是一直增大的,而是先增大后减小,存在极大值;井壁厚度直接影响着刃脚端阻力大小和侧壁摩阻力变化规律,进而间接影响沉井的下沉深度;沉井悬吊力大小随着施工条件的变化而变化,对于沉井设备悬吊能力的设计应根据实际情况进行综合考虑;对于内径6m,厚度0.5m的矿山沉井井壁,在f=8kPa条件下,其最大下沉深度为56m;根据下沉深度设计减阻泥浆性能是控制下沉阻力、实现系统优化的重要手段。

In order to study the variation of the force on the wall of the VSM caisson,the sinking process and the force characteristics of the VSM caisson are analyzed based on the characteristics of the construction technology. First,according to the sinking characteristics of the VSM caisson,the loads received during the construction process are sorted out,and the typical movement state of a sinking cycle of the caisson is divided. Then,based on the GGMeyerhoff formula and specifications,the sinking resistance of the caisson is analyzed and calculated,the calculation formula is proposed for the blade foot resistance considering the flooding in the well,and the construction mechanics model is established for the typical state of the shaft wall;finally,the geometric parameters of the caisson,the sinking resistance,the sinking resistance,and the relationship between sink depth and suspension force are calculated by taking the mine shaft engineering as an example. The results show that,with the increase of the sinking depth,the suspension force of the VSM caisson increases to a maximum value and then decreases;the thickness of the well wall directly affects the resistance and the changing law of the sidewall friction resistance,thus indirectly affects the sinking depth of the caisson;the suspension force of the caisson changes in different construction conditions. The design of the suspension capacity of the caisson equipment should be comprehensively considered according to the actual situation. The mine caisson wall with an inner diameter of 6 m and a thickness of 0. 5 m has a maximum sinking depth of 56 m when f = 8 kPa;and it is an important way to control the sinking resistance and achieve system optimization through designing the performance of friction-reducing mud according to the sinking depth.