三轴加载条件下格架灰岩变形破坏特征与渗透特性演化规律研究

Study on the deformation and failure characteristics and the evolution law of permeability characteristics of lattice limestone under triaxial loading conditions

摘要

自古以来，海洋建设对各国的发展都非常重要。随着“一带一路”和“21世纪海上丝绸之路”倡议的推进，国内对岛礁工程建设的力度不断加大。作为岛礁建设基础的礁灰岩，是珊瑚礁岩土的主要组成部分，其力学性质和渗透特性直接影响着工程的稳定性。然而，不同种类的礁灰岩在强度和渗透率方面存在显著差异，这些差异对工程建设有着重要影响。针对格架灰岩，运用加工后的标准试样，采用全自动GDS三轴渗流试验系统对其进行了应力-渗流耦合试验，分析研究了破坏特征及渗透特性演化规律。研究认为格架灰岩各向力学参数围压效应显著，饱和水的弱化作用对格架灰岩各项力学指标影响较大，且破坏形式也随围压升高变化显著；在不同围压下，格架灰岩渗透率变化规律较好对应了应力-应变曲线；通过分析渗透率损失率(PSL)、渗透率损失系数(EIP)得到格架灰岩渗透特性随围压变化规律。

Abstract

The automatic GDS triaxial seepage test system was used to carry out the stress-seepage coupling test of lattice limestone under seepage conditions. It is concluded that the peak stress and strain of lattice limestone increase with the increase of confining pressure, and the confining pressure effect is significant, and the weakening effect of saturated water has a great influence on the mechanical indexes of lattice limestone. Although the confining pressure increases, the failure mode transitions from X-shaped conjugate inclined shear failure to single-inclined shear failure, and finally presents a penetrating tensile failure form. Under different confining pressures, the permeability of lattice limestone corresponds well to the stress-strain curve. At the same time, the permeability loss rate(PSL) increases with the increase of confining pressure, and the permeability loss coefficient(EIP) is positive in the 1st to 4th stage loading, negative value after the 5th stage loading at low confining pressure, and negative value after the 6th and 7th levels of high confining pressure.

关键词

格架灰岩 / 应力-渗流 / 岩石破坏 / 渗透率演化

Key words

trellis limestone / stress-seepage / rock destruction / permeability evolution

Author summay

赵晟轩(1998—), 男, 硕士研究生, 主要从事格架灰岩渗流研究。E-mail: [e-mail]

基金资助

国家自然科学基金项目(42271026)