Beijing Normal University
the National Key Research and Development Program of China
切沟侵蚀是导致土地退化的重要因素之一。在我国东北黑土区，切沟侵蚀更为严重，且深受冻融作用影响。然而，有关冻融循环对切沟侵蚀评价的研究很少。由于沟壁崩塌是切沟侵蚀对冻融循环的主要响应，所以，可以通过测量冻融循环期间沟壁崩塌体积来评价冻融循环对切沟侵蚀的贡献。2016-2018年间，选取36条切沟共计463个崩塌点开展了野外调查。基于调查结果，切沟沟壁崩塌主要表现为两种类型：块状崩塌和松散堆积。在每一个崩塌点，测量两种堆积体的形态参数：包括崩塌土壤的体积、切沟横断面的宽度和深度，以及相应沟壁土壤的剪切力和硬度。结果表明：（1）三年研究期间冻融作用导致的沟壁崩塌强度平均为16.12 m3/km/y。两种崩塌类型在切沟内随机发生，单点冻融崩塌量主要集中在0-3 m3，但块状崩塌导致的土方量更大。（2）切沟横断面宽度和深度是沟壁崩塌的主要影响因素，崩塌量随宽深比增大而增加，当宽深比>2.71后，崩塌量会迅速增加。（3）切沟崩塌量也与沟壁土壤的剪切力和硬度等紧密相关。研究结果为定量评价冻融循环对切沟侵蚀贡献提供了数据支撑。
Gully erosion is one of the most important factors to cause land degradation. In the black soil area of northeast China, gully erosion is more severe and deeply affected by freeze-thaw effects. However, there is little research on the evaluation of freeze-thaw cycles (FTCs) on gully erosion. Due to the fact that gully wall collapse is the main response of gully erosion to FTCs, the contribution of FTCs to gully erosion can be evaluated by measuring the volume of gully wall collapse during FTCs. Between 2016 and 2018, field investigations were conducted on a total of 463 collapse points in 36 gullies. Based on the survey results, there are two main types of gully wall collapse: massy soil collapse and loose soil accumulation. At each collapse point, measure the morphological parameters of two types of accumulations, including the volume of collapsed soil, the width and depth of the gully cross-section, and the shear force and hardness of the corresponding gully wall soil. The result shows that: (1) the average strength of gully wall collapse caused by FTCs during the three-year study period is 16.12 m3/km/y. The two types of freeze-thaw collapse occur randomly within the gully, with the single point freeze-thaw collapse mainly concentrated in 0-3 m3, but massy soil collapse will produce a larger amount of soil. (2) the width and depth of gully cross-section is the most important factors to induce the collapse of gully wall, furthermore, the volume of collapse soil will quickly increase once the width to depth ratio>2.71. (3) the amount of gully collapse is also closely related to the shear force and hardness of the soil on the gully wall. The research results provide data support for quantitatively evaluating the contribution of FTCs to gully erosion.