基于静力推覆试验的4车道公路隧道围岩压力计算模型研究

Ground pressure calculation model of four-lane highway tunnel based on static pushover tests

以典型4车道公路隧道为原型,开展缩尺模型的静力推覆试验,重点关注地层位移、地层裂缝、围岩压力随推覆位移的发展规律,并与2车道隧道的试验结果展开对比。试验结果表明:(1)地层以起拱线为界发生相反方向位移进而产生裂缝,因此计算模型中起裂点位置应由边墙底部修正为起拱线处。(2)地层在推覆作用下沿隧道环向平顺滑移且大角度偏转倾斜,因此计算模型中潜在滑移面应由恒定竖直修正为线性倾斜。在此基础上,探讨了围岩压力计算模型假定在4车道隧道中的适用性,提出适用于4车道公路隧道的围岩压力修正计算模型。研究成果可为4车道公路隧道的抗震计算/验算提供试验依据与技术支撑,为围岩压力计算模型的进一步完善提供参考。

Using a typical four-lane highway tunnel as a prototype,we conducted static pushover tests on a scaled-down model to examine the variations in ground displacement,ground pressure,and ground cracking with pushover distance.Compared with the test results of two-lane tunnel,the test results indicate that the ground is displaced reversely from the arching line and then cracked.Therefore,the location of fracture point should be modified from the bottom of the side wall to the arching line.The test results also show that the ground slides smoothly along the tunnel circumferential direction with a large inclination angle,so the potential slip planes should be modified from constant vertical to linear inclination.According to these test results,the applicability of surrounding ground pressure calculation model assumption in the four-lane tunnel is discussed,and a modified ground pressure calculation model suitable for the four-lane highway tunnels is proposed.These researches can provide experimental basis and technical support for the seismic calculation/checking of the four-lane highway tunnel,and provide reference for further improvement of surrounding ground pressure calculation model.