不同含水状态下的桂林临桂区滑坡页岩剪切蠕变特性试验研究

Experimental Study on Shear Creep Properties of Landslide Shale in Lingui District, Guilin under Different Water-Containing State

摘要: 本文以桂林临桂区滑坡页岩为研究对象，开展干燥、天然、饱和三种含水状态下的分级剪切蠕变试验，系统分析了含水状态与剪切荷载对页岩剪切力学特性及蠕变规律的影响。结果表明：含水率显著弱化页岩抗剪强度，干燥、天然、饱和状态峰值剪切强度依次为3.19 MPa、2.80 MPa、2.33 MPa，饱和状态较干燥状态降低约27%；各级剪切荷载下，页岩均表现为“瞬时变形–减速蠕变–稳态蠕变”的三阶段蠕变特征，剪切荷载越大，初始瞬时应变与稳态应变越大，进入稳态蠕变的时间越短；含水率放大了蠕变变形并加速了蠕变进程，同一荷载下饱和试样的稳态蠕变应变为干燥试样的1.8~2.3倍，水岩耦合作用是边坡蠕变失稳的关键诱因。研究成果可为桂林地区页岩边坡长期稳定性评价及滑坡防治提供试验依据与理论支撑。

Abstract: This paper investigates the shear creep behavior of landslide shale from Lingui District, Guilin. Graded shear creep tests were conducted under dry, natural, and saturated conditions to systematically analyze the effects of water-containing state and shear load on the shear mechanical properties and creep characteristics of shale. The results show that water content significantly weakens the shear strength of shale: the peak shear strengths of dry, natural, and saturated states are 3.19 MPa, 2.80 MPa, and 2.33 MPa, respectively, with the saturated state reducing by about 27% compared with the dry state. Under all shear loads, the shale exhibits a three-stage creep characteristic of “instantaneous deformation-decelerated creep-steady creep”. The higher the shear load, the larger the initial instantaneous strain and steady-state strain, and the shorter the time to enter the steady-state creep. Water content amplifies creep deformation and accelerates the creep process: under the same load, the steady-state creep strain of saturated samples is 1.8~2.3 times that of dry samples, and the water-rock interaction is the key inducement for slope creep instability. The research results can provide an experimental basis and theoretical support for the long-term stability evaluation and landslide prevention of shale slopes in Guilin area.