Abstract The mechanical characteristics of calcareous silt interlayers play an important role in the stability of island-reef foundations. Direct shear and consolidation tests were performed to study the relationship between the mechanical properties and the physical parameters of calcareous silt. Based on the consolidation test results and analysis of the settling examples, different calculation methods for soil settling were compared. The results show the following. (1) The relationship between the cohesion and water content of calcareous silt can be represented by an M-shaped curve. The water contents corresponding to the two peaks of the M-type curve increase with increasing dry density. (2) When the dry density is less than 1.33 g/cm3, increasing the density significantly improves the internal friction angle of calcareous silts. When the dry density of the calcareous silt is greater than 1.33 g/cm3, the internal friction angle is affected by both the dry density and the water content. (3) The shear strength decreases when the water content exceeds the optimum level. (4) The compressive modulus of calcareous silt is larger than that of terrigenous silt. Specifically, it decreases with decreasing dry density and increasing water content. (5) The stepwise loading method should be used to estimate the soil settling before fill engineering construction.

中文翻译：

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水力充填岛礁中钙质粉砂的力学特性

摘要 钙质粉砂夹层的力学特性对岛礁地基的稳定性起着重要作用。通过直剪固结试验研究钙质粉土力学性能与物理参数之间的关系。根据固结试验结果和沉降实例分析，比较了不同土壤沉降计算方法。结果如下。(1) 钙质粉土的黏聚力与含水量的关系可用M型曲线表示。M型曲线的两个峰对应的含水量随着干密度的增加而增加。(2)当干密度小于1.33 g/cm3时，增加密度显着提高钙质粉土的内摩擦角。当钙质粉土的干密度大于1.33 g/cm3时，内摩擦角受干密度和含水量的影响。(3)当含水量超过最佳水平时，剪切强度降低。(4) 钙质粉土的压缩模量大于陆源粉质。具体来说，它随着干密度的降低和含水量的增加而降低。(5) 填土工程施工前应采用逐步加载法估算土壤沉降量。它随着干密度的降低和含水量的增加而降低。(5) 填土工程施工前应采用逐步加载法估算土壤沉降量。它随着干密度的降低和含水量的增加而降低。(5) 填土工程施工前应采用逐步加载法估算土壤沉降量。