渤海海底土类动剪切模量比和阻尼比试验研究

Experimental Study on Dynamic Shear Modulus Ratio and Damping Ratio of the Soils of Bohai Seafloor

土的动剪切模量比和阻尼比是工程场地地震安全性评价工作和土层地震反应分析中不可缺少的重要参数。本文采用应力控制振动三轴试验装置对渤海海底的常规土类动剪切模量比G/G_(max)和阻尼比λ进行试验研究,试验装备为HX-10O控制振动三轴试验系统,土类包括粘土、粉质粘土、细砂、粉砂、粉砂质细砂,土样来自渤海海域内BZ13-1、BZ26-2、QK18-2等3油田的场地钻孔。采用拆线曲线拟合动剪切模量比G/G_(max)、阻尼比λ随动剪应变γ变化的关系,得到各类上的G/G_(max)、λ随γ变化关系及推荐值。本文的结果已在这3个油田平台的地震安全性评价中使用,本项工作积累的有关基础资料和工作方法可供该海域内有关海洋建设工程的地震安全性评价工作以及未来海域内的地震区划工作借鉴和参考。

The dynamic shear modulus ratio and damping ratio of soil are indispensability for seismic safety evaluation and soil layer seismic response analysis of engineering sites. In this paper, using the apparatus and method of stress-controlled cyclic triaxial test, an experimental study on dynamic shear modulus ratio and damping ratio for the soils of Bohai seafloor is performed. The test apparatus is HX100 cyclic triaxial test system. The soil samples, including clay, silty clay, fine sand, silty sand, silty fine sand, sampled from QK18-2, BZ13-1 and BZ26-2 oilfields of Bohai sea. The relations of G/Gmax-γ and λ-γ are fitted by two hyperbolic equations, and the curves and recommended values of G/Gmax-γ and λ-γ for each soil are obtained. These results have been used in the seismic safety evaluation of these oil platforms and also have an important reference for other engineering constructions in the sea area. Furthermore, the results of the paper can provide the related basic data and work method for a future seismic zoning of Chinese sea area.