Gradation and Rheological Characteristics of Glacial Debris Flow along the Kangding–Linzhi Section of Sichuan–Tibet Railway

Shuliang Liu,Wubin Wang,Jichun Zhang,Xie Cheng,Hongtao Jiang,Chong Xu

doi:10.1155/2020/8886137

Shuliang Liu, Wubin Wang + Show 4 more

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https://doi.org/10.1155/2020/8886137

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Abstract

To date, most research on the characteristics of glacial debris flow along the Sichuan–Tibet railway has focused on numerical simulations and remote sensing, resulting in a lack of direct experimental data from debris flow samples. Therefore, in the present study, a field investigation was conducted along the Sichuan–Tibet railway, and 55 samples of glacial debris flow deposits were systematically analyzed to determine their grading and rheological properties. This is the first systematic experimental study on glacial debris flow deposits. The results showed that the proportion of coarse particles was high and the proportion of fine particles was low in the glacial debris flow along the Sichuan–Tibet railway. The average gravel and sand contents were 37.8% and 58%, respectively, and the average contents of silt and clay were 3.7% and 0.47%, respectively. The average fractal dimension was 2.1507, which is much greater than that of viscous debris flow. Under the same gravity and shear rate, the stress of typical glacial debris flow was significantly less than that of viscous debris flow, whereas the variability of the stress was more significant. These findings will contribute to revealing the movement rules and disaster risk of glacier debris flow along the Sichuan–Tibet railway and have considerable theoretical and practical significance for ensuring safety during both its construction and later operation.

Highlights

Debris flow is a natural phenomenon that typically occurs in mountainous and hilly regions. is phenomenon is characterized by a long incubation period, sudden outbreaks, and strong destructive power, is difficult to predict, and typically results in serious casualties [1,2,3,4]
An ice lake that burst in Midui Gully resulted in a flood and debris flow in 1988 that completely destroyed more than 40 km of the Sichuan–Tibet highway [10,11,12]. erefore, revealing the regularity of occurrence and the factors that influence the degree of hazard has considerable value in ensuring the safety of construction and operation of the Sichuan–Tibet railway. e main criteria of viscous debris flow and glacial debris flow are as follows: e debris flow with glacier activity in the gully can be called a glacial debris flow. e content of viscous particles in this kind of debris flow is small, and the gravity of debris flow is usually less than 15 kN/m3
An analysis of the grading data from 26 samples of glacial debris flow in Table 1 shows that the average percent gravel across samples is 37.8% with a standard deviation of 13.6%, and the maximum and minimum values were 67.5% and 12.8%, respectively. e grading data had a normal distribution (p > 0.05) as indicated by the normality test and distribution curve in Figure 6(a), which indicates that the sampling was representative

Summary

Introduction

Debris flow is a natural phenomenon that typically occurs in mountainous and hilly regions. is phenomenon is characterized by a long incubation period, sudden outbreaks, and strong destructive power, is difficult to predict, and typically results in serious casualties [1,2,3,4]. Debris flow is a natural phenomenon that typically occurs in mountainous and hilly regions. Debris flow is an enormous threat to railway construction, in the mountainous and hilly regions of Southwest China, where debris flow frequently occurs. E construction of the Sichuan–Tibet railway faces considerable geological challenges such as substantial changes in terrain height, strong plate activity (geological fracturing and high-intensity earthquakes), frequent mountain disasters, and a fragile ecosystem. E construction of the Sichuan–Tibet railway will encounter interference and destruction from various mountain disasters, of which debris flow is the most serious event [5, 6]. Most of the viscous debris flows are caused by rainfall, the clay content is relatively large, and the debris flow gravity is usually greater than 15 kN/m3, which is more common in Southwest China (Yunnan and Sichuan)

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