青藏铁路碎石护坡-热管复合措施的补强效果研究

青藏铁路高温冻土区的普通路基和保温材料路基均处于热不稳定状态, 需要对它们增设碎石护坡-热管复合措施来强化处理, 新增设的补强措施对路基下部冻土的保护效果如何是人们极为关心的问题. 因此, 对北麓河高温高含冰量路段增设了碎石护坡及热管的复合补强措施后路基下部土体的热状态进行观测.结果显示:普通路基在增设补强措施后, 人为冻土上限进一步抬升, 阴阳坡下均出现显著的降温趋势, 且路基下温度场逐渐趋于对称, 降温范围逐渐向路基中心及深部发展, 路堤中心深部地温仍处于增温状态, 但增温趋势明显缓减; 保温材料路基在增设补强措施后, 人为冻土上限也进一步的抬升至保温板附近, 融化夹层在2个冻融周期后消失, 路堤中心温度在2个冻融周期后出现了降温趋势. 这些效果说明, 补强措施在调控路基内部及下部多年冻土温度时发挥了积极作用.

The coupled reinforcing effect of crushed rock slope protection and thermosyphons in Qinghai-Tibet Railway

General embankment and embankment with heat insulating material on the Qinghai-Tibet Railway are proved to be thermal instable in warmer permafrost regions, so, effective reinforcement with crushed rock slope protection and thermosyphon is urgent. The practical effect of the implement of protect underlying permafrost is a matter of great public interest. Therefore, thermal state of the embankments in warmer and ice-rich permafrost regions in Beiluhe after crushed rock slope protection coupled with thermosyphon is investigated. The results indicated that (1) when the general embankment is reinforced with crushed rock slope protection coupled with thermosyphon, artificial permafrost table further uplifts, and ground temperature under both the left and the right shoulder decreases distinctly, with a tendency that the temperature field is getting more and more symmetry. What''s more, the temperature decreasing range is enlarging and extending downwards. However, ground temperature in the deeper layer under the central embankment is still increasing, with a diminishing increasing rate; (2) when the heat insulating embankment reinforced with crushed rock slope protection coupled with thermosyphon, artificial permafrost table is further uplifting to the vicinity of the insulating layer; besides, residual thawed layer disappears and ground temperature under the central embankment begins to decrease after two frozen-thaw cycles. Thus, reinforcement of crushed rock slope protection coupled with thermosyphon plays an active role in controlling the ground temperature within the embankment and the permafrost beneath.