空洞对隧道结构安全影响试验与模拟

Test and simulation of influence of voids on tunnel structure safety

为减少衬砌背后空洞对隧道结构的危害,采用模型试验和数值模拟相结合的方法,通过变化空洞数量、位置和尺寸3个参数,研究空洞对二次衬砌结构安全性的影响规律。结果表明:空洞导致衬砌结构安全系数发生显著降低,尤其是空洞同时存在于拱顶、拱底和左右拱腰时,拱脚安全系数变化最为明显,降低了57%;对于2处空洞组合的情况,左右拱腰同时出现空洞时衬砌结构的受力最为不利,安全系数最低;拱顶空洞环向宽度范围由0°增加至45°的过程中,拱顶弯矩由正转负,安全系数先增大后减小,当空洞范围为45°时拱顶安全系数最小,仅为15°时的34%。

In order to reduce damage of voids behind lining to tunnel structure,influence of voids on safety of secondary lining structure was studied through changing parameters like number,location and size of voids by using model test and numerical simulation.The results show that safety factor of lining structure is significantly reduced by voids,especially when they exist at the same time in vault,bottom and left and right waist of the arch.Changes in safety factor of arch foot is the most obvious,which decreases by 57%.For cases of two voids at the same time,that at left and right arch waist is most unfavourable to stress of lining structure,featuring the lowest safety factor.When vault void increases from 0°to 45°,the vault bending moment changes from positive to negative,and its safety factor firstly increases and then decreases,during which,it will be the smallest when circumferential angle is 45°,only 34%of that at 15°.