高應(yīng)力下粗砂與混凝土接觸面剪切特性影響因素試驗(yàn)研究

檀俊坤 郭佳奇 徐子龍 劉希亮

摘 要：利用改裝自RMT-150B的直剪試驗(yàn)儀在不同法向應(yīng)力下進(jìn)行了含水量為0%、8%、16%、24%的粗砂與具有4種不同粗糙度、強(qiáng)度混凝土基底的接觸面直剪試驗(yàn)。試驗(yàn)結(jié)果表明：當(dāng)法向應(yīng)力等于2 MPa時(shí)，隨接觸面粗糙度的增加，達(dá)到極限抗剪強(qiáng)度的剪切位移先增加后減小;當(dāng)法向應(yīng)力大于2 MPa時(shí)，達(dá)到極限剪切強(qiáng)度的剪切位移基本不再隨接觸面粗糙度而變化;在法向應(yīng)力相同的情況下，干砂初始抗剪剛度較濕砂大。依據(jù)試驗(yàn)數(shù)據(jù)回歸分析可知：高應(yīng)力直剪條件下，粗砂與混凝土接觸面的剪應(yīng)力 剪切位移關(guān)系可用雙曲線模型描述。直觀分析結(jié)果表明：極限抗剪強(qiáng)度受法向應(yīng)力影響最大，且與應(yīng)力呈線性相關(guān)，其次為接觸面粗糙度，含水量的影響略高于混凝土界面強(qiáng)度;初始抗剪剛度隨法向應(yīng)力、接觸面粗糙度、基底硬度的增大而增大，接觸面初始剪切剛度所受因素影響從大到小依次為法向應(yīng)力、含水量、接觸面粗糙度、基底硬度;顆粒相對(duì)破碎受法向應(yīng)力影響最大，其次為含水量，再次為基底硬度，接觸面粗糙度影響最小，并且顆粒相對(duì)破碎隨法向應(yīng)力增達(dá)而增大，隨混凝土粗糙度與基底硬度的增大而減小，隨含水量增加存在破碎的破碎峰值。

關(guān)鍵詞： 接觸面;正交試驗(yàn);極限抗剪強(qiáng)度;初始剪切剛度;相對(duì)破碎

中圖分類(lèi)號(hào)：TU753.3

文獻(xiàn)標(biāo)志碼：A? 文章編號(hào)：1674-4764（2018）06-0067-09

Experimental investigation of the influential factors on the shear

characteristics of the interface between coarse sand

and concrete under high stress

Tan Junkun，Guo Jiaqi，Xu Zilong，Liu Xiliang

（School of Civil Engineering，Henan Polytechnic University，Jiaozuo 454003，Henan，P.R. China）

Abstract：The direct shear apparatus amended from the RMT-150B system is adopted to conduct the direct shear test on the coarse sand with the water contents of 0%， 8%，16% and 24%， respectively. The contact surfaces with four kinds of concrete basements with different roughness and strengths under different normal stresses are considered. The results have proved that the ultimate shearing strength under high stress increases with the normal stress. The shearing rigidity decreases with the shear displacement development while the initial shearing rigidity decreases when the normal stress increases. The shear displacement keeps increasing as the roughness of the contact surface grows up to a normal stress of 2 MPa. The initial shearing rigidity of the dry sand with the water content of 0% is greater than that of the wet sand under the same normal stress. Regression analysis based on the experimental data? shows that the displacement for the contact surface between the coarse sand and concrete under the high-stress direct shear conditions can be described via the hyperbolic model. In addition， the ultimate? and initial shearing strength of the contact surface? can be estimated through the regression parameters. It has been shown that the ultimate shearing strength is the most significantly influenced by the normal stress? followed by the roughness of the contact surface， and? the influence of the water content is slightly greater than the strength of the concrete interface. The relative crushing ration of particles is subjected to the significant influence from the normal stress， followed by the water content and basement hardness and the influence from the contact surface roughness is minimum. In addition， the relative crushing ratio of particles increases as the normal stress develops and decreases while the concrete roughness and basement hardness become smaller. The peak of the existing crush increased with the water content.