Particle breakage of calcareous sand in high stress condition will affect its stability of engineering.Under the confined conditions,the mixed group of calcareous sand grain size of which is within 0.25mm ～0.5mm,1 mm～2mm,2mm ～5mm and of different initial density is loaded under high pressure with hydraulic universal testing machine.The influence of factors including termination pressure,average grain size and dry density is studied on its particle breakage.The results show that termination pressure of P value has a great significance to relative particle breakage of Br value and the correlation between P value and Br value fitted with Slogistic function is significant.According to the fitting curves,the breakage process could be divided into two stages:graduallyincreasing stage and slowly-increasing stage;and there is a negative linear correlation between relative particle breakage of Br value and average grain size of d50 value;the deformation-controlling rate and termination pressure are the same,the loading rate is faster when dry density of samples is larger,the relative breakage of Br value is slightly more than that of samples with smaller dry density;under the same termination pressure,the particle breakage of mixed grain group of Br value is much smaller than that of single group;the high pressure loading results in a significant change of gradation and percent of calcareous sand.The influence of high pressure on the engineering properties should be fully taken into consideration.The conclusions of the experiment provide reference for engineering construction of calcareous sand districts in marine sedimentary facies.%高应力环境中钙质砂的颗粒破碎会影响其工程稳定性,利用液压万能试验机在侧限条件下对0.25mm～0.5mm、1 mm～ 2mm、2mm～ 5mm粒径和混合粒组钙质砂进行高压加载,研究终止压力、平均粒径、干密度等因素对其颗粒破碎影响.试验结果表明:终止压力P值对钙质砂颗粒相对破碎率Br值影响显著,用Slogistic函数拟合后相关性良好,根据拟合曲线可将破碎分为渐增和缓增阶段;同时相对破碎率Br与试样平均粒径d50呈线性负相关;控制变形速率和终止压力相同,干密度大的试样加荷速率更快,相对破碎率B,比干密度低的试样略大;同等终止压力水平下混合粒组钙质砂相对破碎率B,远小于单粒组;高压加载导致级配和粒组百分含量变化十分显著,工程中应充分考虑其对钙质砂工程性质的影响.试验结论对海相钙质砂区域工程建设具有参考意义.
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