基于孔压静力触探(CPTU)及扁铲侧胀试验(DMT)南沙软土力学特性研究

Study on the Mechanical Properties of Soft Soil in Nansha Based on CPTU and DMT

基于南沙地区深厚软土地基含水量高、高压缩性、低渗透性、地基承载力低的特征。为获取软土工程特性及力学参数,为南沙深厚软土力学性能指标取值的合理性提供行之有效的判定方法,首先利用原位测试技术孔压静力触探试验(CPTU)、扁铲侧胀试验(DMT)测定软土不排水抗剪强度和变形参数,并对比两种原位测试参数的沿深度变化的发展规律;其次通过统计与回归相结合的方法建立了CPTU与DMT参数的线性回归关系、压缩模量E_(s)与杨氏模量E_(u)的线性回归关系。研究结果表明:软土的不排水抗剪强度σ_(u)、压缩模量E_(s)、不排水杨氏模量E_(u),CPTU试验与DMT试验两种测试结果存在线性拟合关系;CPTU试验和DMT试验检测所得的不排水杨氏模量Eu与压缩模量E_(s)存在线性拟合关系。

Based on the characteristics of high water content,high compressibility,low permeability and low bearing capacity of deep soft soil foundation in Nansha area.In order to obtain the engineering characteristics and mechanical parameters of soft soil and provide an effective method for determining the rationality of the mechanical properties of deep soft soil in Nansha,firstly,the undrained shear strength and deformation parameters of soft soil were measured by using the in-situ test technology of porestatic penetration test (CPTU) and flat shovel side expansion test (DMT).The development law of the two in-situ test parameters along the depth is compared.Secondly,the linear regression relationship between CPTU and DMT parameters,the linear regression relationship between compression modulus Es and Young’s modulus E_(u) were established by combining statistics and regression methods.The results show that there is a linear fitting relationship between the undrained shear strength Su,compression modulus Es,undrained Young’s modulus E_(u),CPTU test and DMT test of soft soil.The undrained Young’s modulus (E_(u)) measured by CPTU and DMT tests has a linear fitting relationship with the compression modulus (E_(s)).