影响疏浚珊瑚礁岩抗剪强度的关键因素

Key factors affecting the shear strength of dredged coral reef

依据疏浚工程珊瑚礁岩的物理力学试验资料,应用珊瑚礁沉积原理和结构特征理论知识,将疏浚珊瑚礁岩分为3类:管状珊瑚礁岩、蜂窝状珊瑚礁岩和致密状珊瑚礁岩。从珊瑚礁岩的特性角度出发,分析了礁岩类别、颗粒成分和破坏应变率对抗剪强度的影响及规律。结果表明:1)粘聚力c和内摩擦角φ均具有无填充管状珊瑚礁<填充珊瑚砂粒蜂窝状珊瑚礁<填充钙质胶结方解石致密状珊瑚礁的特点。2)内摩擦角φ值与粒径大于5 mm的含量值相关性最好,回归系数为0.862。3)c和φ值随轴向应变的增加而迅速增加,抗剪强度达到峰值,所需应变率为0.018%~0.082%,都为脆性破坏,呈现剪切、劈裂和沿裂隙破坏3种形式。

Based on the physical and mechanical test data of dredged coral reef, applying the theory of coral reef deposition and structural characteristics,the dredged coral reef rock are divided into three categories：tubular coral reef,honeycomb coral reef and dense coral roof. From the perspective of coral reef characteristics,this paper analyzes the influence of reel type,particle composition and failure strain rate on the shear strength.These results show that： 1） cohesion（ c） and internal friction angel（ φ） have the same rule： tubular coral reef without filling honeycomb coral reef with filling coral sand dense coral roof with filling calcium cemented calcite.2） The correlation between the internal friction angel（ φ） and the content of particle size greater than 5 mm is the best,whose regression coefficient is 0. 862. 3） c and φ increase rapidly with the increase of axial strain.When shear strength reaches the peak value,the required strain rate is 0. 018% ~ 0. 082%. The damage types of coral reef are always in three forms of shear,split and crack rupture.