隧道洞顶围岩竖向全位移量测及变化规律研究

Study of site monitoring of vertical full displacement of vault surrounding rock of tunnels and its change law

围岩内部位移通常是在工作面开挖后再进行量测,因而导致现场量测结果存在一定损失。为得到隧道施工过程中围岩内部位移的变化规律,自行研制开发了适用于量测隧道洞顶围岩竖向全位移的多点位移测试仪,该仪器具有测试原理简单、现场埋设方便、测试数据精度高的特点,且比传统多点位移计的测点多。结合阿拉坦隧道,利用该仪器对隧道洞顶处的围岩内部位移进行了量测,得到了隧道浅埋段洞顶围岩内部位移的变化规律,经分析发现,如果采用传统多点位移计进行洞内量测围岩内部位移的方式,围岩内部位移的损失程度将达25%以上,这将给围岩稳定性的判定造成直接影响;此外,通过对监控数据的分析,还得到了隧道开挖引起的围岩松弛范围。其结果对隧道的开挖与支护具有重要指导意义。

The internal displacements of surrounding rock are generally surveyed after the excavation of working face, which results in a certain measuring loss for the field observation. In order to get the change law of its internal displacements during tunnel construction, the multipoint-displacement testing equipment is developed, which is applicable to measuring the vertical full displacement of the vault surrounding rock. This equipment is featured by the simple test principle, the convenient field planting and the high-accuracy test data, and it has more measuring points than that of the traditional multipoint-displacement testing equipment has. The internal displacements of vault surrounding rock of the Alatan tunnel is measured by this equipment to obtain its change law in the tunnel＇s shallow section. It shows that if the internal displacements of surrounding rock are generally surveyed by the traditional multipoint-displacement testing equipment, 25 percent of internal displacements of surrounding rock is lost through analysis. The range of the surrounding rock relaxation is found through surveyed data, the result is significant to the tunnel＇s excavation and supporting.