地下多洞室结构的中隔墙安全度区间计算方法

针对地下工程中相邻洞室和隧道群的中隔墙稳定性问题，提出一种基于虚拟应力系数原理的多洞结构中隔墙安全度定量计算方法。该方法通过迭代搜索一个虚拟应力系数K，使得在K倍初始地应力下洞群中隔墙正好出现贯通性的等效塑性应变带，并由此确定中隔墙安全度的下限值。同时，分析不同虚拟应力作用下中隔墙等效塑性应变带两侧特征点的相对变形特征曲线，以相对变形曲线出现突变拐点时对应的虚拟应力系数作为中隔墙安全度的上限值，从而获得中隔墙的安全度区间。通过对一物理模型试验结果的验证分析和西南一大型水电地下洞群中隔墙安全度的计算表明，该方法可以合理地给出中隔墙的安全区间，可为地下多洞室或隧道群中隔墙的安全性定量评价和支护设计提供科学依据。

Interval analysis method of safety degree for mid partition in underground multi-cavern structure

Since the safety of mid partition is an important issue in underground multi-cavern structure, a method is proposed to calculate the safety degree of mid partition quantitatively based on fictitious stress coefficient theory. In the method, a special fictitious stress coefficient K is sought to meet the condition that the equivalent plastic strain runs through the partition exactly under the K times initial geostress, which is the down limit of safety degree. At the same time, the up limit of safety degree is found by analyzing the inflexion point of curve between opposite deformation of typical points at partition and fictitious stress coefficient. So, the safe interval is gained for the stability assessing of mid partition in multi-cavern. Verification of a physical model test and application of multi-cavern indicate that the interval calculation method is reasonable to assess the safety of caverns and tunnels and is useful to optimize the supporting proposal of mid partition.