【摘要】 南水北调工程、青藏铁路建设工程等一系列工程的实施,将进一步影响和加剧青藏高原多年冻土区斜坡稳定性问题,冻土区边坡开挖及斜坡稳定性是工程活动中必须解决的问题之一,冻土斜坡稳定性研究在国内尚属空白。通过相似模型试验对高原多年冻土区斜坡在自然和人类活动影响下的失稳机制和活动规律进行分析,是开展研究的重要手段。根据相似理论第一定律,对冻土斜坡模型试验进行了相似分析,应用积分类比法推导并建立了冻土斜坡模型试验的相似指标和相似判据,得出在用原状土作模型介质时,6个相似常数减少为2个相似常数,即cτ和cl。模型与原型的时间比例尺是由几何比例尺决定的,即cτ=c2l,仅有一个相似参数为自变量,另一个为因变量。据此对青藏高原多年冻土区青藏公路沿线K3035处冻土斜坡进行了相似模型设计和冻融模型试验。模型再现了K3035处7°斜坡在4个冻融循环条件下,坡体中部(水平、垂向)4#位移伸张计质点位移曲线随时间的变化特征。实验表明,斜坡土体中部在第一次冻融循环中已有滑动迹象,随着滑坎进一步后退和靠近观测基准点,必然出现一次较大的位移,直至周边土体出现滑塌为止。模型试验结果与现场观测资料相比较是令人满意的。更多还原

【Abstract】 A series of construction engineering, such as water resources allocation from south China to north China , Qinghai-Tibet railway construction will affect the slope stability of frozen soil region of Tibet plateau. Model experiment method is an important means to study the instability mechanism affected by natural forces and human activities for frozen slope in Tibet plateau region. According to the 1st law of simulation theory, simulation analysis for frozen slope has been carried out and simulation criterion and index has been set up by using integrated analogy method. It is concluded that 6 simulation parameters can be decreased to 2 and relationship c_τ=c~2_l between 2 parameters will be satisfied. The frozen slope simulation model design and experiment for permafrost at K3035 of Qinghai-Tibet highway based on simulation analysis has been completed. It is shown that characteristics of displacement with time for middle point of slope during 4 freeze-thaw cycles can be observed from simulation model experiment. Experiments also show that slide evidence of middle part of slope soil mass has appeared during first freeze-thaw cycle, and with retrogressive thaw flow slide, slide steep will become next to observing point, a vast scale of slide will certainly take place, till appearance of thaw slumping. Rationality and validity of model design for frozen soil slope has been verified by model test results.更多还原