单轴压缩条件下溶蚀礁灰岩细观变形破坏特征研究

礁灰岩的溶蚀对海洋工程和岛礁工程的稳定性有明显的影响.孔隙型溶蚀是礁灰岩常见的溶蚀方式.本文通过构建随机溶蚀孔洞的离散元模型,模拟孔洞型溶蚀礁灰岩的细观变形破坏特征,分析其变形破坏规律与裂隙演化特征.结果 表明,基于随机聚类算法构建的溶蚀礁灰岩离散元模型能够很好地模拟孔洞型溶蚀作用,且其变形破坏特征具有明显的规律;随着溶蚀率的增加,溶蚀礁灰岩单轴应力应变曲线由单峰型逐渐转变为双峰型或多峰型,破坏特征由脆性破坏逐渐转变为塑性破坏;随着溶蚀率的增加,礁灰岩单轴抗压强度和弹性模量都逐渐减小,抗压强度呈指数函数下降,弹性模量呈线性函数下降,而泊松比则表现为先增后降,说明试样在高溶蚀率时主要发生结构性破坏;随着溶蚀率增加,礁灰岩的宏观破裂面逐渐消失,由于溶蚀孔洞的相互作用,导致了起源于孔洞周围的裂隙开始萌生,并逐渐贯通,最终导致试样发生整体宏观破坏.本研究成果可为深入认识海洋工程和岛礁工程中溶蚀礁灰岩的变形破坏特征提供理论参考.

Study on the microstructure and failure characteristics of limestone in dissolution reef under uniaxial compression

Dissolution of reef limestone has a significant impact on the stability of ocean engineering structures and island reef engineering structures,Cavernous dissolution is a common dissolution method for reef limestone.By constructing a discrete element model of random dissolved holes,the meso-deformation and failure characteristics of cave-type dissolved reef limestone are simulated,and its deformation and failure laws and fracture evolution characteristics are analyzed.The results show that the discrete element model of dissolving reef limestone based on stochastic clustering algorithm can well simulate the pore-type dissolution,and its deformation and failure characteristics have obvious rules;with the increase of the dissolution rate,the uniaxial stress-strain curve of the dissolution reef limestone gradually changes from unimodal to bimodal or multimodal,and the failure characteristics gradually change from brittle to plastic.With the increase of the dissolution rate,the uniaxial compressive strength and elastic modulus of reef limestone gradually increases.The compressive strength decreases exponentially,the elastic modulus decreases linearly,and the Poisson''s ratio increases first and then decreases,indicating that the sample mainly undergoes structural damage at a high corrosion rate;as the corrosion rate increases the macro fracture surface of the reef limestone gradually disappears.Due to the interaction of dissolving pores,the cracks originating around the pores begin to sprout and gradually penetrate,eventually leading to the overall macroscopic destruction of the sample.The results of this research can provide a theoretical reference for the in-depth understanding of the deformation and failure characteristics of dissolved limestone in marine engineering and island reef engineering.