In view of the characteristics of soft soil deep foundation pit for the construction and geotechnical characteristics of the special medium,it is difficult to calculate theoreti- cally accurately structural deformatio...In view of the characteristics of soft soil deep foundation pit for the construction and geotechnical characteristics of the special medium,it is difficult to calculate theoreti- cally accurately structural deformation of the foundation pit,so in the course of excavation on the construction of the information is particularly important.The analysis and compari- son of several popular non-linear forecasting methods,combined with the actual projects, set up a grey theoretical prediction model,time series forecasting model,improved neural network model to predict deformation of the foundation pit.The results show that the use of neural network to predict with high accuracy solution,it is the foundation deformation prediction effective way in underground works with good prospects.展开更多
In view of the collapse of a deep excavated foundation pit of the Xianghu subway underground station in Hangzhou of China,the main features of the accident are analyzed,and the induced factors of the accident are summ...In view of the collapse of a deep excavated foundation pit of the Xianghu subway underground station in Hangzhou of China,the main features of the accident are analyzed,and the induced factors of the accident are summarized. Then,a 3-D FEM analysis model is created to demonstrate the soil-support structures interaction system,and the effect of the main factors,such as the volume replacement ratio of the bottom soil reinforcing,the asymmetric ground overload,the embedded depth of the diaphragm wall,the shear strength of the bottom soils disturbed by the construction,and the excessive excavation of the bottom soil,are analyzed and compared. The results show that the ineffective original reinforcement plan for the bottom soft soil is the most prominent factor for the accident,and the disturbance effect of the deep excavation on the shear strength of the bottom soft soil is another significant factor for the accident. Meanwhile,if the reinforcement of the bottom soft soil is canceled,an appropriate extension of the diaphragm retaining walls to the under lying harder soil layer can also effectively prevent the collapse of the deep excavated foundation pit. In addition,the partly excessive excavation in the process has a great influence on the axial force of the most nearby horizontal support but few effect on the stability of the diaphragm wall. Thus,the excessive excavation of the bottom soils should not be the direct inducing factor for the accident. To the asymmetric ground overload,it should be the main factor inducing the different damage conditions of the diaphragm walls on different sides. According to the numerical modeling and actual engineering accident condition,the development process of the accident is also identified.展开更多
深海管线通常铺设于海床表面,在自重和铺管作业的影响下会嵌入海床,其嵌入深度w_(ini)显著影响海床对管线的侧向土阻力。现有研究多聚焦于嵌入深度较浅情况(w_(ini)=0.1D~0.5D,D为管径),而最新调查表明,部分管线嵌入深度已超过0.5D。为...深海管线通常铺设于海床表面,在自重和铺管作业的影响下会嵌入海床,其嵌入深度w_(ini)显著影响海床对管线的侧向土阻力。现有研究多聚焦于嵌入深度较浅情况(w_(ini)=0.1D~0.5D,D为管径),而最新调查表明,部分管线嵌入深度已超过0.5D。为揭示更大嵌入深度下管-土相互作用机制,采用径向基点插值法-网格重剖分和小应变插值技术(radial point interpolation method-remeshing and interpolation technique with small strain,简称RPIM-RITSS)数值方法,对嵌入深度为0.1D~1.0D的管线开展了管-土侧向相互作用大变形数值分析。通过与已有相关离心机试验及数值结果对比,验证了该数值方法的有效性。在此基础上,深入分析了管线嵌入深度和重量对其侧向屈曲模式和土阻力的影响,据此提出了适用于嵌入深度为0.6D~1.0D的残余侧向屈曲土阻力预测模型,以期为深海管线的侧向稳定性和安全评估提供参考。展开更多
A study is presented on the dynamic analysis of a tracked vehicle for mining on the deep seabed of very soft soil. Equations for the interaction between the track and extremely soft seabed are employed to develop a tr...A study is presented on the dynamic analysis of a tracked vehicle for mining on the deep seabed of very soft soil. Equations for the interaction between the track and extremely soft seabed are employed to develop a track/soil interaction module called TVAS. The vehicle is modeled as a multibody dynamic system by the use of a multibody dynamic analysis program. The module developed is cooperated with the multibody dynamic analysis program with a user-defined subroutine. The dynamic behavior and the conceptual design of the mining vehicle on the deep seabed are investigated.展开更多
基金the Educational Department of Liaoning Province Through Scientific Research Project(20060051)National Natural Science Foundation of China(50604009)Universities Excellent Talents Support Plan to Train Foundation of Liaoning(RC-04-13)
文摘In view of the characteristics of soft soil deep foundation pit for the construction and geotechnical characteristics of the special medium,it is difficult to calculate theoreti- cally accurately structural deformation of the foundation pit,so in the course of excavation on the construction of the information is particularly important.The analysis and compari- son of several popular non-linear forecasting methods,combined with the actual projects, set up a grey theoretical prediction model,time series forecasting model,improved neural network model to predict deformation of the foundation pit.The results show that the use of neural network to predict with high accuracy solution,it is the foundation deformation prediction effective way in underground works with good prospects.
基金funded by the China Postdoctoral Science Foundation(No. 2014M551909)the Jiangsu Geology & Mineral Exploration Bureau’s Science Foundation(No.2013-KY-13)
文摘In view of the collapse of a deep excavated foundation pit of the Xianghu subway underground station in Hangzhou of China,the main features of the accident are analyzed,and the induced factors of the accident are summarized. Then,a 3-D FEM analysis model is created to demonstrate the soil-support structures interaction system,and the effect of the main factors,such as the volume replacement ratio of the bottom soil reinforcing,the asymmetric ground overload,the embedded depth of the diaphragm wall,the shear strength of the bottom soils disturbed by the construction,and the excessive excavation of the bottom soil,are analyzed and compared. The results show that the ineffective original reinforcement plan for the bottom soft soil is the most prominent factor for the accident,and the disturbance effect of the deep excavation on the shear strength of the bottom soft soil is another significant factor for the accident. Meanwhile,if the reinforcement of the bottom soft soil is canceled,an appropriate extension of the diaphragm retaining walls to the under lying harder soil layer can also effectively prevent the collapse of the deep excavated foundation pit. In addition,the partly excessive excavation in the process has a great influence on the axial force of the most nearby horizontal support but few effect on the stability of the diaphragm wall. Thus,the excessive excavation of the bottom soils should not be the direct inducing factor for the accident. To the asymmetric ground overload,it should be the main factor inducing the different damage conditions of the diaphragm walls on different sides. According to the numerical modeling and actual engineering accident condition,the development process of the accident is also identified.
文摘深海管线通常铺设于海床表面,在自重和铺管作业的影响下会嵌入海床,其嵌入深度w_(ini)显著影响海床对管线的侧向土阻力。现有研究多聚焦于嵌入深度较浅情况(w_(ini)=0.1D~0.5D,D为管径),而最新调查表明,部分管线嵌入深度已超过0.5D。为揭示更大嵌入深度下管-土相互作用机制,采用径向基点插值法-网格重剖分和小应变插值技术(radial point interpolation method-remeshing and interpolation technique with small strain,简称RPIM-RITSS)数值方法,对嵌入深度为0.1D~1.0D的管线开展了管-土侧向相互作用大变形数值分析。通过与已有相关离心机试验及数值结果对比,验证了该数值方法的有效性。在此基础上,深入分析了管线嵌入深度和重量对其侧向屈曲模式和土阻力的影响,据此提出了适用于嵌入深度为0.6D~1.0D的残余侧向屈曲土阻力预测模型,以期为深海管线的侧向稳定性和安全评估提供参考。
文摘A study is presented on the dynamic analysis of a tracked vehicle for mining on the deep seabed of very soft soil. Equations for the interaction between the track and extremely soft seabed are employed to develop a track/soil interaction module called TVAS. The vehicle is modeled as a multibody dynamic system by the use of a multibody dynamic analysis program. The module developed is cooperated with the multibody dynamic analysis program with a user-defined subroutine. The dynamic behavior and the conceptual design of the mining vehicle on the deep seabed are investigated.
