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为研究不同粗糙度结构面在长期荷载下的强度变化规律,选取Barton标准剖面为人工模拟结构面的表面形态,并用水泥砂浆浇筑,试样成型后,对其进行直接剪切试验以及剪切蠕变试验,基于试验结果,建立瞬时剪切强度公式,并对不同粗糙度结构面的剪切蠕变特征进行分析,提出确定长期强度的方法,并以此求解长期强度,进而分析粗糙度对结构面剪切时效特征的影响,研究成果表明:随着粗糙度的增大,蠕变整体位移减小,蠕变破坏曲线越来越陡,其蠕变速率以及剪切刚度在大于某个应力值时,相对于前一级均会发生显著变化;瞬时强度与长期强度均与粗糙度呈线性关系,随着粗糙度的增大,长期强度与瞬时强度的比值减小,这是连续完整岩石与不连续贯通的结构面具有不同的时效特征以及不同法向应力和粗糙度下剪切面积比的变化共同造成的,另外等速率曲线拐点法得到的长期强度符合蠕变特征变化得到的长期强度范围,其合理性和可靠性得到了验证。
In order to study the strength variation regularity of different roughness surface under long-term load, the Barton standard section was selected as the surface morphology of the artificial structure surface and poured with cement mortar. After the sample was formed, the direct shear test and shear creep Based on the test results, the formula of instantaneous shear strength is established and the shear creep characteristics of different roughness surface are analyzed. The method of determining the long-term strength is put forward to solve the long-term strength, and then the influence of roughness on the structure The research results show that as the roughness increases, the overall creep displacement decreases, the creep failure curve becomes steeper and steeper, and the creep rate and shear stiffness are higher than a certain value When compared with the previous stage will have significant changes in both instantaneous strength and long-term strength and roughness are linear relationship with the roughness increases, the ratio of long-term strength and instantaneous strength is reduced, which is a continuous complete rock and Discontinuous through the structural surface has different characteristics of aging and different normal stress and roughness under the shear area ratio change caused by the other equal rate curve inflection point obtained Strength in line with long-term creep strength range of features to get change, the rationality and reliability has been verified.