摘要
首次利用钻孔旁压仪对青藏公路沿线典型地段多年冻土的力学性质进行了原位测试 .利用平面弹性体理论和Lame提出的无限弹性介质中的圆柱孔穴径向膨胀方程对试验曲线进行解译 .结果表明 ,冻土的旁压模量、旁压比例界限、极限压力随着温度的降低而增大 ;含水量在一定范围内变化时冻土的旁压模量、旁压比例界限、极限压力与之呈正相关 ,当其超过一定限度时它们之间呈负相关 ;容重与冻土的旁压模量、旁压比例界限、极限压力呈正相关 .低温冻土较高温冻土稳定 .
In this article, the authors suggested, first in China, how to determine the mechanical properties of frozen soils along the Tibetan Highway by using a preboring pressuremeter test(BPT), and how to use the plainplastic theory and the radial expansive equation of cylinder cave in infinite elastic medium provided by Lame to interpret the results of the BPT. How to deal with the initial data got from the test can be described as follows. First, correcting the initial volume values got from the volume gauge directly. Secondly, correcting the initial pressure values got from the pressure gauge directly by using the results got from the pressure correction table. Thirdly, drawing the relative curves of volume versus pressure by using the corrected data. These curves could give a lot of useful information of the frozen soils, which were tested on. The mechanical properties of frozen soils, such as the pressuremeter proportional limitation, the limited pressure, etc., could be gained from the curves. At last, the pressuremeter modulus and the shear modulus of the frozen soils can be calculated. Analysis shows that both the pressuremeter modulus and other mechanical parameters (including pressuremeter proportional limitation and limited pressure) of frozen soils increase with decreasing temperature; the mechanical parameters of frozen soils increase when water content of frozen soils increasing in acertain range, but decrease when a limited water content is exceeded; the mechanical parameters of frozen soil increase with density of frozen soil increasing; frozen soils in low temperature area with anannual mean temperature lower than -1.5 ℃ is more stable than that in temperate area with anannual mean temperature higher than -1.0 ℃. At the same time, some inevitable problems met in the in situ test arediscussed,and the physical meanings of the pressuremeter modulusand the pressuremeter proportional limitationare analyzed too.
出处
《冰川冻土》
CSCD
北大核心
2000年第4期366-371,共6页
Journal of Glaciology and Geocryology
基金
中国科学院"九五"重点项目!(KZ95 2 J1 2 16 )
中国科学院寒区旱区环境与工程研究所知识创新项目!(2 10 0 5 3)资助
关键词
原位试验
冻土
钻孔旁压仪
力学性质
含水量
pressuremeter
in situ test
mechanics of frozen soil
frozen soi4
