海相软土无侧限抗压强度曲线类型分类及影响因素  

CLASSIFICATION OF UNCONFINED COMPRESSIVE STRENGTH CURVE TYPES AND INFLUENCING FACTORS OF MARINE SOFT SOILS

作　　者：苟富刚[1] 龚绪龙[1] GOU Fugang;GONG Xulong(Geological Survey of Jiangsu Province,Key Laboratory of Earth Fissures Geological Disaster,Ministry of Natural Resources,Nanjing 210049,China)

机构地区：[1]江苏省地质调查研究院,自然资源部地裂缝地质灾害重点实验室,南京210049

出　　处：《工程地质学报》2025年第1期20-28,共9页Journal of Engineering Geology

基　　金：连云港城市地质调查项目(资助号:20170821);中国地质调查局项目(资助号:1212011220005);国家自然科学基金项目(资助号:41772327).

摘　　要：无侧限抗压强度是岩土设计中的一种代表性强度。基于连云港地区186组海相软土无侧限抗压强度试验(UTC),对其应力-应变曲线类型进行了分类统计,探讨了影响应力-应变曲线的因素。研究结果表明:应力-应变曲线类型可以归为3个类型。Ⅰ类曲线为软化型,具有明显的轴向应力峰值,Ⅰ类曲线数量占比27%;Ⅱ类曲线为稳定性,不具有明显的峰值,一般应变大于15%后轴向应力才趋向一个定值,Ⅱ类曲线数量占比35%;Ⅲ类曲线为应变硬化型,应变大于20%时轴向应力还没有收敛趋势,Ⅲ类曲线数量占比38%。振动可以促使应力-应变曲线类型由Ⅰ型逐渐转化为Ⅲ型,且破坏应变随着振动时长的增加而变大,无侧限抗压强度数值逐渐减小。取样器类型也对曲线类型有显著影响,Ⅰ类曲线中采用薄壁获取样品的占比90%,厚壁获取样品仅占比10%。K_(0)固结预处理可以恢复土体地应力,促使曲线类型由Ⅱ、Ⅲ型转化为Ⅰ型,获取的抗剪强度接近原位试验获取的土体抗剪强度,且随着取样深度的增加,进行土体应力恢复效果越明显。The unconfined compressive strength is a representative strength in geotechnical design.Based on 186 sets of unconfined compression test(UTC)of marine soft soils in Lianyungang area,the stress-strain curve types were classified and statistically discussed,and the factors affecting the stress-strain curve were discussed.The results showed that the stress-strain curve types can be categorized into three types.Type Ⅰ curves are softening type,with obvious peak axial stress,and the number of type Ⅰ curves accounts for 27%;Type Ⅱ curves are stable,without obvious peak,and the axial stress generally converges to a constant value only after the strain is greater than 15%.The number of Type Ⅱ curves accounts for 35%;Type Ⅲ curves are strain-hardening type.When the strain is greater than 20%,the axial stress has not yet converged,and the number of type Ⅲ curves accounts for 38%.Vibration can lead to the gradual transformation of the stress-strain curve type from type Ⅰ to type Ⅲ,and the damage strain becomes larger with the increase of vibration duration,and the value of unconfined compressive strength gradually decreases.The type of sampler also has a significant effect on the curve type.90%of the type Ⅰ curves are obtained by thin-walled samples,and only 10%of the type Ⅰ curves are obtained by the thick-walled samples.K_(0) consolidation pretreatment can restore the soil ground stress and promote the curve type to be transformed from type Ⅱ and Ⅲ to type Ⅰ.The obtained shear strength is close to the soil shear strength obtained from the in-situ test,and the more obvious the soil stress recovery effect is carried out with the increase of sampling depth.

关 键 词：无侧限抗压强度试验 应力-应变 K_(0)固结 薄壁取样器 抗剪强度 

分 类 号：P642.3[天文地球—工程地质学]