【作者】 赵晨；

【导师】 黄晓明；

【作者基本信息】 东南大学 ， 交通运输工程， 2015， 硕士

【摘要】 随着公路事业的发展,高等级宽幅公路逐渐向青藏高原多年冻土区延伸。由于宽幅路基结构总吸热面积和总体积热容的增加以及全球气候变暖的影响,路基及基底多年冻土温度升高,冻土人为上限下移,路基结构易发生热融沉降变形。‘青藏高原多年冻土对温度敏感性大,EPS隔热层路基、碎(块)石路基和热棒路基等工程措施在现有道路工程中的应用效果较好,但是对于宽幅路基的处治效果还需要进一步研究讨论。本文以温度场的数值模拟结果为基础,对多年冻土区无工程措施的宽幅路基、隔热层宽幅路基以及隔热层与换填碎石复合路基的温度场分布特征进行研究分析,主要包括以下几个方面：论文首先基于多年冻土区路基温度场数值计算、模型参数以及边界条件的相关理论,结合青藏高原地区气候环境及多年冻土的特征,建立了路基温度场数值计算的控制方程,确定了土体的热物理参数以及边界条件,给出了多年冻土区路基温度场有限元数值模拟的理论基础、材料参数及边界条件。其次,在对比了不同宽度和高度的普通路基温度等值线图、地温沿深度随时间的变化曲线图以及年最大融深随时间的变化曲线图的基础之上,研究分析了路基的尺寸效应对路基温度场的影响规律,计算表明宽幅路基结构的热稳定性差,且路基越高,稳定性越好,并指出多年冻土区无工程措施的宽幅路基的合理填筑高度为4m-6m。第三,论文基于温度场的数值模拟结果,对隔热层路基的工程应用效果进行了研究分析,计算结果表明隔热层路基的热稳定性明显提高,且隔热层埋深越浅、厚度越大,温度稳定性越好,并根据保温效果和行车要求指出隔热层的合理厚度为0.15m-0.25m,合理埋深为0.5m-1.0m。最后,论文根据隔热层路基人为上限位置确定换填碎石层厚度,并对复合路基结构的保护效果进行数值模拟,并根据数值模拟结果提出隔热层与换填碎石复合路基的隔热层合理厚度与换填碎石合理深度的组合,隔热层厚度为0.08m-0.1m,换填碎石深度为3-5m。更多还原

【Abstract】 As the development of expressways in China, high grade roads with wide pavem ents are gradually developed in the permafrost regions. The increase of total heat abso rption area and volumetric heat capacity in wide embankment structure and rise of te mperature in embankment and basal permafrost can lead to the melt of permafrost un der embankment settling diseases as the artificial frozen soil under the ceiling move. Permafrost in Qinghai-Tibet Plateau is sensitive to temperature. The actual application of EPS insulation board, block-rock-embankment and thermal probe performed efficient ly. However, the effect of applications has yet to be studied and discussed for wide e mbankment. Based on the numerical simulation results, this paper analyzed the emban kment temperature field of normal roadbed, insulation board roadbed and insulation bo ard-replacement gravel roadbed. And the main topics of this paper are as follows:First, this paper built the control equation of numerical simulation of embankment temperature field based on the theories of numerical simulation of embankment tempe rature field, model parameter and boundary conditions. The thermophysical parameter o f permafrost and boundary conditions was determined considering the climatic environ ment and characteristics of permafrost in Qinghai-Tibet Plateau.Second, this paper compared the temperature contour map, the curve of temperatu re along the depth over time and the graph of annual maximum thaw depth over time. Then the size effect on embankment temperature field was analyzed and the results s howed that the stability of wide embankment was poor, and it improved when the em bankment was higher.. It proposed that the reasonable filling height of embankment wi thout engineering measures was 4-6m.Third, this paper studied the effect of engineering application of insulation emban kment and proposed that the stability improved of insulation embankment with thicker insulation layer and lower depth. It suggested that the reasonable thickness was 0.15-0.25m and the depth was 0.5-1.0m.Last, this paper studied the effect of engineering application of block-rock-embank ment and recommended the reasonable insulation board, along with the appropriate de pth of replacement gravel, according to the numerical simulation results. It suggested t hat the appropriate thickness was 0.08m-0.10m and the depth was 3-5m.更多还原