Isotropic compression tests were conducted on a series of gap-graded mixtures of a carbonate sand (CS) from the South China Sea and a fine crushed quartz silt. The purpose of these tests is to explore breakage mechanism of CS particles under varying fines content (FC). The weaker CS originally exhibited a unique compression line, whereas the stronger quartz silt originally had a stable soil fabric leading to non-convergent compression lines. It was found that the threshold FC indicating a change from CS to silt-dominated soil matrix, together with the suppression of particle breakage, have governed the change from converging to non-converging compression behaviour and from non-stable to stable soil fabric for these gap-graded soil mixtures. For FC ≤ 30%, the soil mixtures exhibited a unique compression line due to the substantial breakage of the weaker CS particles in the CS-dominated soil matrix. However, non-convergent compression lines were observed for the soil mixtures with FC ≥ 40% (threshold FC). It can be explained due to inability of weaker CS particles to participate in load bearing of the silt-dominated soil matrix. There was insignificant particle breakage of the CS with the initial soil fabric remaining stable at high stress.

中文翻译：

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颗粒破碎对间隙梯度碳酸盐砂-粉砂混合料压缩特性的影响

对来自南海的碳酸盐砂（CS）和细碎石英粉砂的一系列间隙分级混合物进行了各向同性压缩试验。这些测试的目的是探索细粉含量（FC）变化下CS颗粒的破碎机理。较弱的CS最初显示出独特的压缩线，而较强的石英粉砂最初具有稳定的土壤结构，导致压缩线不收敛。发现阈值FC指示了从CS到粉砂为主的土壤基质的变化，并抑制了颗粒破碎，从而控制了从收敛到不收敛的压缩行为，以及从不稳定到稳定的土壤结构的变化。间隙分级的土壤混合物。如果FC≤30％，由于CS占主导地位的土壤基质中较弱的CS颗粒的大量破坏，土壤混合物表现出独特的压缩线。但是，对于FC≥40％（阈值FC）的土壤混合物，观察到非收敛的压缩线。可以解释这是由于较弱的CS颗粒无法参与以粉砂为主的土壤基质的承载。CS的颗粒破碎不明显，初始土壤织物在高应力下保持稳定。