中文摘要：

对不同含水率及干密度增量的珊瑚砂微生物固化体进行了无侧限抗压强度试验和电镜扫描试验,研究含水率对不同干密度增量固化体的应力-应变曲线特征、无侧限抗压强度、弹性模量和微观结构的影响。结果表明：不同含水率的固化体受压后呈脆性破坏,应力-应变曲线形态类似,均为应变软化型,破坏应变随含水率的增高而减小。固化体的无侧限抗压强度随含水率的增高而减小,含水率从0%增高到15%后固化体强度的减小幅度最高达33.5%,且干密度增量越大,强度的减小幅度越大;弹性模量随含水率的增高呈现先增大后减小的趋势。珊瑚砂颗粒破碎与碳酸钙胶结被水弱化均会降低固化体的强度和弹性模量,不同含水率和干密度增量对结构的强度特性产生了不同的影响,并综合影响了固化体的力学特性。不同含水率的固化体受压破坏后的微观结构具有差异,含水率为0%的固化体颗粒破碎现象较为明显,含水率为15%的固化体碳酸钙胶结的断裂和剥落更严重。

英文摘要：

To explore the influence of moisture content on characteristics of stress-strain curves, unconfined compressive strength,elastic modulus and microstructure of biocemented coral sand columns,unconfined compressive strength test and microscopic structure scan of biocemented coral sand columns with different moisture contents and increment of dry density were conducted. The test result showed that characteristics of stress-strain curves of biocemented coral sand columns with different moisture were similar,the curves were all strain-softening and the failure modes were brittle failure,and the failure strain decreased with the increase of moisture content. The unconfined compressive strength of biocemented coral sand columns decreased with the increase of moisture content,the reduction of unconfined compressive strength could reach 33. 5% with the moisture content being increased from0% to 15%,and the reduction of unconfined compressive strength increased with the increase of increment of dry density; the elastic modulus increased at first,then turned to decrease with the increase of moisture content. The particle breakage of coral sand and calcium carbonate cement weakening by water resulted in the decrease of unconfined compressive strength and elastic modulus of biocemented coral sand columns,while that two factors played different roles in different conditions of moisture content and increment of dry density,thus influenced the mechanical properties of biocemented coral sand columns. The microstructure of biocemented coral sand columns with different moisture contents were different,the particle breakage was more apparent with the moisture content of 0%,while the fracture and peeling of calcium carbonate cement were more serious with the moisture content of 15%.