滑坡失稳预测一直是滑坡研究的重点和难点，而水又是绝大多数滑坡在自然条件下致滑的关键因素，特别是在黄土地区，由于黄土的水敏性很强素有“十坡九水”之说。临界状态线可以直观揭示滑坡发生时滑带土的临界应力状态，因此，通过研究滑带土含水率与临界状态线的定量关系，可以判断滑带土是否破坏，对滑坡的预测提供依据。为进一步研究黄土滑坡预测的方法，提出了应用滑带土的临界状态线来预测，首先以正城滑坡滑带土为研究对象，开展了不同含水率下的固结不排水三轴试验（CU试验）研究，得到各个含水率下的临界状态线，并以抗剪强度参数为桥梁，推导出土的临界状态线与对应含水率之间的相关关系。试验结果表明：滑带土的临界状态线在不同的含水率下表现为参数为不同的斜直线，其截距和斜率与抗剪强度参数有关，水通过影响滑带土的抗剪强度参数决定着滑带土的临界状态，在含水率为15.28%之后，含水率高的滑带土临界状态线更靠近下方；黏聚力c随含水率先增大后减小，最大值为134.72 kPa；内摩擦角φ则随含水率增大呈降低趋势，而且c对水的敏感度更高。最后，利用柳林县贺西滑坡的勘察资料及经验数据，说明了临界状态线在预测滑坡失稳中的可行性，并得出滑坡发生时达到临界状态线的滑带土占比约60%，从而为预测滑坡发生提供一定指导。

The prediction of landslide failure has always been a hot and difficult topic in the study of landslides. Water is the key factor for most landslides to slip under natural conditions，especially in the loess area.Because the water sensitivity of loess is very strong，it is known as “Nine out of ten landslides are caused by water”.The critical stress state of slip zone soil can be described by critical state line (CSL) directly when the landslide occurs. Therefore，it can provide a basis for the prediction of landslides through studying the quantitative relationship between water content and critical state and determining if the slip zone soil is destructed. For studying the prediction method of loess landslide，the critical state line of slip zone soil is applied. Firstly，taking slip zone soil of Zhengcheng landslide as subject，consolidated undrained triaxialshear test (CU test) under different water contents were conducted. The critical state lines of various moisture contents are obtained. Taking the shear strength parameters as bridge，the relationship between the moisture content and corresponding critical state line of soil has been deduced. The results show that：critical state lines under different water contentsare different obliquestraight lines related with shear strength parameters,and critical state of slip zone soil is determined by water through shear strength parameters. After the water content is 15.28%，the critical state line of slip zone soil with high moisture content is closer to the bottom; The cohesion c increases first and then decreases with the water content，and the maximum value is 134.72 kPa; But the internal friction angle φ decreases with the increase of water content，and the sensitivity of c value to water is higher. In the end，by using the exploration data and empirical data of Hexi landslide in Liulin County，the feasibility of the critical state line in the prediction of landslide instability is explained. It is also concluded that the proportion of slip zone soil reaching the critical state line when the landslide occurs is about 60%.Which can provide guidance for the occurrence of loess landslide.