衬砌渠道为防止冻胀因素的破坏,一般都在衬砌体下面铺筑砂砾垫层。实践证明,衬砌渠道的渠底及坡脚附近的冻胀破坏较侧坡上部严重,也就是说,衬砌渠道横断面的下部冻害较上部严重。故在实际施工中采用边坡的垫层厚度与渠底不同,边坡的垫层也是上部薄下部厚,即属楔形垫层。其优点和等厚度垫层相比较工程量小。有些渠道根据其走向及光照条件,又有阴坡和阳坡之分,而阴坡冻害又较阳坡严重,为了减少工程量 Lining channels In order to prevent the destruction of frost heaving factors are generally paved under the lining of gravel cushion. Practice has proved that the bottom of the lining channel and the slope near the foot damage frost heave than the upper part of the slope, that is to say, the lining of the lower section of the cross-section of the lower frost damage than the upper. Therefore, in actual construction, the thickness of the cushion used by the slope is different from that of the canal bottom. The cushion of the slope is also thick at the lower part of the upper part, which is a wedge-shaped cushion layer. Its advantages and the thickness of the cushion compared to a small amount of engineering. Some channels according to their direction and light conditions, there are shady slopes and sunny points, and cold frost damage than the sunny slope, in order to reduce the amount of work