摘要
杭州东城文体公园段的软土层从地表至深部的含砂率、含水率、颗粒组分均有所不同,通过三轴压缩试验分析了不同土层土样的力学特性,建立了基于Drucker-Prager屈服准则的残余强度指标确定方法,提出了能有效反映含砂土样抗开挖扰动能力的扰动损伤系数概念,对不同土层土样的开挖扰动损伤特性进行分析.结果显示:由于软土中砂的空间分布不均匀,因此应变软化型软土试样呈明显的剪切裂缝破坏形式;随着土样中含砂率的增加,土样的抗剪强度明显增大,但峰值应变明显减小;粉黏夹粉土的抗剪强度随着其含水率的增大而降低;对含砂率高和含水率高的地层进行开挖扰动时,建议采用允许应变量进行安全控制;杭州东城文体公园段的软土层中,(2)粉土的抗开挖扰动能力最差,(3)粉土夹砂次之,(1)、(4)粉黏夹粉土和(5)粉黏夹砂的抗开挖扰动能力则相对较好;采用所提出的方法确定不同土层土样的残余强度指标值时,(2)粉土的残余强度指标值受残余应变取值的影响最大,(3)粉土夹砂次之,(1)、(4)粉黏夹粉土及(5)粉黏夹砂最小.该研究可为附近地区开挖扰动控制及数值模拟参数选择提供理论依据.
The sand content,water content and particle composition of sandy soil layers in the Dongcheng Cultural and Sports Park section of Hangzhou are different from the surface to the deeper layers.The mechanical properties of soil simples in different soil layers were analyzed through triaxial compression tests.A method for determining the residual strength index based on the Drucker-Prager yield criterion was established.The concept of disturbance damage coefficient,which can effectively reflect the disturbance resistance capability of sandy soil samples during excavation,was proposed.The analysis of the disturbance damage characteristics during excavation was conducted for soil samples in different soil layers.The results showed that due to the uneven spatial distribution of sand in the soft soil,the strain-softening type soil samples exhibited distinct shear cracks and failure modes.With the increase of the sand content in the soil samples,the shear strength of the soil samples significantly increased,but the peak strain decreased noticeably.The shear strength of silty clay with silt decreased with the increase of water content.When excavating soil layers with high sand content and high water content,it is recommended to control the strain within a permissible limit for safety.In the soft soil layers of the Dongcheng Cultural and Sports Park section in Hangzhou,the disturbance resistance capability during excavation of②silt was the worst,followed by the③silt with sand,while the①、④silty clay with silt and⑤silty clay with sand showed relatively better resistance to excavation disturbance.When determining the residual strength index values for soil simples in different soil layers by using the proposed method,the residual strength index value of②silt was most affected by the residual strain value,followed by the③silt with sand,①、④silty clay with silt and⑤silty clay with sand.This study can provide a theoretical basis for excavation disturbance control and parameter selection of numerical simulations in the nearby areas.
作者
沈才华
董玉翔
胡昱业
陈晓峰
SHEN Caihua;DONG Yuxiang;HU Yuye;CHEN Xiaofeng(College of Civil and Transportation Engineering,Hohai University,Nanjing 210098,China;Hangzhou Communications Investment Technology Engineering Co.Ltd.,Hangzhou 310024,China;Zhejiang Shuzhi Communication Technology Co.Ltd.,Hangzhou 310006,China)
出处
《河南科学》
2023年第7期1046-1054,共9页
Henan Science
基金
国家自然科学基金(41830110,52278400)
浙江省交通运输厅科技计划项目(2022-GCKY-12)
江苏省交通运输厅科技示范项目(2022Y04)。
关键词
含砂软土
三轴压缩试验
力学特性
扰动损伤系数
残余强度指标
soft soil with sand
triaxial compression test
mechanical properties
disturbance damage coefficient
residual strength index
