横波可控震源振动器—大地耦合振动数值模拟  

Numerical simulation of shear-wave seismic vibrator-ground coupled vibration system

作　　者：彭珣 郝磊 PENG Xun;HAO Lei(School of Mechanical Engineering,Southwest Petroleum University,Chengdu,Sichuan 610500,China;BGP Inc.,China National Petroleum Corporation,Zhuozhou,Hebei 072751,China)

机构地区：[1]西南石油大学机电工程学院,四川成都610500 [2]中国石油集团东方地球物理公司,河北涿州072751

出　　处：《石油地球物理勘探》2023年第6期1349-1358,共10页Oil Geophysical Prospecting

基　　金：国家自然科学基金项目“复杂地表条件下横波可控震源振动器—大地相互作用机理及激振性能研究”(42202348);四川省自然科学基金项目“多非线性作用下横波可控震源振动器—大地耦合振动机理与激发适配性研究”(2023NSFC0769)联合资助。

摘　　要：横波可控震源与大地之间的耦合振动关系复杂,涉及非均匀接触、土壤弹塑性、摩擦、埋深等多种非线性影响因素,但现阶段尚未见横波可控震源振动器—大地耦合振动实用模型及其响应特性的系统研究。为此,基于有限元法建立了考虑多种非线性影响因素的横波可控震源振动器—大地耦合振动三维数值仿真模型,从接触界面应力分布与变形、振动输出力、激发应力波传播以及能量传递特性等方面深入分析了振动器—大地耦合振动响应特性,同时研究了土壤类别、弹性模量、黏度等地表条件参数对响应特性的影响规律。结果表明:受加载方式及土壤塑性变形的影响,振动器两侧平板与大地的接触不对称,易引发平板的局部脱耦;振动器的有效水平输出力仅为接触力的一部分,其应力波曲线存在明显的谐波畸变;振动器传递给大地的有效能量较有限,耦合系统的有效能量传递率很低;土壤参数对振动器的输出以及能量传递特性影响显著,振动器在黏土中的激发效果更好,土壤弹性模量是振动器平板是否脱耦的主控因素,土壤黏聚力的增加能显著改善系统的能量传递特性。因此,利用数值模拟可有效分析振动器—大地耦合振动响应,可为横波可控震源振动器结构设计及优化等提供理论参考。The interaction between the shear-wave seismic vibrator and the ground is complicated,and involves uneven contact,soil plasticity,friction,and burial depth.However,there are rare references in the systematic research on the coupled vibration of the shear-wave vibrator-ground systems.Thus,this paper builds a three-dimen-sional numerical simulation model of a shear-wave seismic vibrator-ground system considering multiple nonlinear factors.The coupled vibration characteristics of the system are analyzed from aspects of the strain distribution and deformation at the contact interfaces,the vibration output force,the shear wave propagation,and the energy transfer characteristics.Meanwhile,the effects of soil types,elastic modulus,and cohesion on the response characteristics of the system are investigated.The results show that there is contact asymmetry between the vibrator plate and ground due to the load mode and the soil plastic deformation,which can bring about local decoupling of the plate.The effective output force of the vibrator is only a part of the contact force,and there are obvious harmonic distortions in the generated seismic waves.The effective energy transferred from the shear-wave vibrator to the ground is limited,with a low effective energy transfer ratio of the coupling system.The soil parameters have a significant influence on the vibrator output and energy transfer characteristics,and the vibrator operates better in clay soil.Additionally,the soil elastic modulus is the main controlling factor for the vibrator plate decoupling,while increasing the soil cohesion can improve the energy transfer characteristics of the system.Therefore,numerical simulation can analyze the coupled vibration characteristics of the shear-wave vibrator-ground system,providing theoretical references for the structural design and optimization of the vibrators.

关 键 词：横波可控震源 振动器—大地耦合振动 响应特性 有限元法 仿真模型 地表条件参数 

分 类 号：P631[天文地球—地质矿产勘探]