砂土质隧道围岩粘聚力影响因素的试验研究

Test research for influencing factors of the cohesive strength of sand soil tunnel surrounding rock

隧道围岩中较差的砂土质隧道围岩一般在洞口段较为常见。砂土具有粘聚力是客观事实,该粘聚力会对砂土质围岩稳定性产生较大影响。本文从影响砂土质围岩坑道稳定性因素及围岩稳定性分类的角度出发,探讨了与砂土质隧道围岩稳定性相关的粘聚力的影响因素,发现砂土的密实程度对砂土围岩粘聚力有较显著的影响;细粒(d<0.075mm)含量对粘聚力的影响规律与砂土密实程度有关;采用细粒含水量而不是砂土含水量的方法来评定潮湿砂土的粘聚力的影响是较为合理的方法,并总结了细粒含水量对砂土粘聚力的影响规律。

Sand soil surrounding rock, the comparatively unstable part of tunnel, is common at the portal section. It is an objective fact that the sand soil has cohesive strength that exerts influence on the stability of sand soil surrounding rock. From the perspective of influencing factors of the stability of sand soil surrounding rock and the stability classification of surrounding rock, this paper explores the influencing factors of cohesive strength which are related to the stahility of sand soil surrounding rock. It is discovered that the degree of compaction of sand soil has certain influence on the cohesive strength of it; the influencing law of clay content （d 〈 0.75mm） to the cohesive strength is relevant to the degree of compaction of sand soil. It is more rational to adopt the water content of clay rather than water content of sand soil to access the cohesive strength of moist sand soil. This article also makes a conclusion for the influencing rules of the water content of clay to the cohesive strength of sand soil.