青藏铁路路基下高温-高含冰量冻土旁压试验研究

为研究青藏铁路路基下高温-高含冰量冻土的力学性质，在青藏铁路北麓河试验段开展一系列旁压强度试验。试验研究表明：路基的增加引起路基下多年冻土温度升高，未冻水含量增加，最终导致冻土旁压临塑压力Pf下降31 %，旁压极限压力Pl下降44 %，旁压剪切模量Gm下降80 %。对于高温冻结黏土，富冰冻土和饱冰冻土Gm对温度变化的敏感性高于含土冰层；饱冰冻土的Pf和Pl对温度变化的敏感性高于富冰冻土和含土冰层。

Study on warm and ice-rich permafrost beneath Qinghai-Tibet Railway embankment with pressiometer

In order to study the mechanics characters of the warm and ice-rich permafrost beneath the embankment of Qinghai-Tibet Railway, a series of pressiometer tests were conducted in the Beiluhe test site of Qinghai-Tibet Railway. The tests results indicate that: the temperature of the permafrost beneath the embankment gets higher; unfrozen water of the permafrost increases; the critical plastic load Pf descends 31 %; the ultimate load Pl descends 44 % and the shear modulus Gm descends 80 % because of the embankment. For warm permafrost, the sensitivities of shear modulus Gm to the temperature of both ice-saturated and ice-rich permafrost are higher than that of ice with soil inclusions; the sensitivities of the critical plastic load Pf and the ultimate load Pl to the temperature of ice-saturated permafrost are higher than that of ice-rich permafrost and ice layer with soil inclusions.