引黄济宁工程隧洞第三系软岩物理力学及变形特征初步研究

Preliminary Study on the Physical Mechanics and Deformation Characteristics of the Tertiary Soft Rock in the Yellow River to Xining water diversion project

摘要:

青海省引黄济宁工程隧洞第三系地层分布范围广,隧洞埋深大。针对隧洞第三系地层围岩稳定性问题,采用试验及经验分析的方法进行了第三系地层软岩物理力学及变形特征初步研究。结果表明：第三系地层岩石密度较低,吸水率较高；饱和状态下岩石单轴抗压强度急剧降低,软化系数极低；部分岩性具有膨胀性；少量岩性耐崩解性较差；引黄济宁工程隧洞第三系地层岩石在富水条件下力学性能差,对围岩稳定不利。当埋深大于127m时,引黄济宁工程隧洞第三系围岩可能产生严重-极严重挤压变形,施工中应根据围岩变形特征,有针对性地采取工程措施,以减少围岩变形的危害。

关键词:引黄济宁工程;隧洞;第三系地层;物理力学特性;强度应力比;挤压变形

Abstract:

The distribution range of the tertiary strata in the tunnel of the Yellow River to Xining water diversion project in Qinghai Province is wide, and the tunnel burial depth is deep. A preliminary study on the physical mechanics and deformation characteristics of soft rock in the tertiary strata of tunnels surrounding rock was conducted using experimental and empirical analysis methods. The results showed that the rock density of the tertiary strata is low and the water absorption rate is high; Under saturated conditions, the uniaxial compressive strength of rocks decreases sharply, and the softening coefficient is extremely low; Some rock types have expansibility; A small amount of rock has poor resistance to disintegration; The mechanical properties of the rock in the tertiary strata of the Yellow River to Xining water diversion project are poor under water rich conditions, which is detrimental to the stability of the surrounding rock. When the burial depth is greater than 127m, the tertiary surrounding rock of the Y Yellow River to Xining water diversion project tunnel may undergo severe to extremely severe compression deformation. During construction, targeted engineering measures should be taken based on the deformation characteristics of the surrounding rock to reduce the harm of surrounding rock deformation.

Key words:Yellow River to Xining water diversion project; Tunnel; Tertiary strata; Physical and mechanical properties; Strength-stress ratio; Compressional deformation