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Cumulative Deformation of Soft Clay Under Cyclic Loading

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China Ocean Engineering 1993年第3期8卷 341-348页

作者： yan, shuwang yan, Chi Zhang, Jianguo Tianjin Univ Tianjin China

Reconstituted specimens are prepared by means of vacuum preloading. Both static and cyclic triaxial tests are carried out, with the specimens consolidated under different principal stress ratios. A finite element meth... 详细信息

关键词： Deformation Finite element method Loads (forces) Materials testing Ocean engineering Pore pressure Specimen preparation Stresses

Analysis of Pipeline Damage to Impact Load by Dropped Objects

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Transactions of Tianjin University 2006年第B9期12卷 138-141页

作者： yan shuwang TIAN Yinghui School of Civil Engineering Tianjin University Tianjin 300072 China

Marine pipeline damage subjected to dropped objects from platforms or supply vessels is analyzed to introduce an easy and applicable approach to investigating the damage induced by impact load from drop weight. A practical engineering example was presented and analyzed using the commercial program 'ANSYS/LS-DYNA', which is a powerful tool with an explicit dynamic solver. And rational agreement of the results with previous works was obtained. The suggested procedure might be taken as a checking analysis of the protection measures of pipelines in addition to the general risk assessment method.

关键词： pipeline dropped objects damage impact load ANSYS/LS-DYNA

Stability Design System of Submarine Pipelines

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China Ocean Engineering 1995年第1期10卷 115-120页

作者： Gao, Yinli yan, shuwang Wang, Jinying

This paper introduces a stability design system of submarine pipelines. The system can provide a reasonable design procedure for users with reference to domestic and foreign methods and in the light of home engineerin... 详细信息

关键词： submarine pipeline stability design wave DnV specifications earthquake

Difficulties and measures of driving super long piles in Bohai Gulf

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Theoretical & Applied Mechanics Letters 2015年第2期5卷 69-73页

作者： shuwang yan Jia Li Liqiang Sun Guomin Sun School of Civil Engineering Tianjin University China Offshore Oil Engineering Co.

Long piles of the ocean oil platform are usually manufactured as the integration of several segments, which have to be assembled one by one during installation. During pile driving, excessive pore pressure will build up in such a high level that hydraulic fracturing in the soil round the pile may take place, which will cause the soil to consolidate much faster during pile extension period. Consequently, after pile extension, the soil strength will recover to some extent and the driving resistance will increase considerably, which makes restarting driving the pile very difficult and even causes refusal. A finite element （FE） analysis procedure is presented for judging the risk of refusal by estimating the blow counts after pile extension, in which the regain of soil strength is considered. A case analysis in Bohai Gulf is performed using the proposed orocedure to exolain the nile refusal phenomenon.

关键词： Super long pile driving Refusal Excessive pore pressure Hydraulic fracture Finite element analysis Prevent measures

大直径超长桩后继打桩拒锤现象分析及单桩承载力计算

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岩石力学与工程学报 2008年第A2期27卷 3459-3464页

作者：刘润闫玥闫澍旺天津大学建筑工程学院天津300072

受到海上施工条件的限制,特别是大直径超长桩的施工常出现停锤,停锤后继续打桩时,连续打桩引起的桩周地基土中的超静孔隙水压力消散,土体强度得到恢复和提高,使得打桩阻力增大,甚至出现拒锤现象。分析表明,地基土层的分布、土体中裂缝... 详细信息

受到海上施工条件的限制,特别是大直径超长桩的施工常出现停锤,停锤后继续打桩时,连续打桩引起的桩周地基土中的超静孔隙水压力消散,土体强度得到恢复和提高,使得打桩阻力增大,甚至出现拒锤现象。分析表明,地基土层的分布、土体中裂缝的开展、停打时间的长短以及桩管内土塞的作用直接影响土体强度的恢复和提高程度。提出超静孔隙水压力的计算方法以及超静孔隙水压力的时间效应;结合一维应力波动理论,以实测打桩记录为依据,采用反分析方法确定当后继打桩出现拒锤现象时的单桩承载力。实际工程算例和海上原位动测结果表明,该方法具有可行性。

关键词：桩基工程打桩分析拒锤强度增长单桩承载力

Settlement and Stability Analysis on Soft Clay Under Cyclic Loading

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China Ocean Engineering 1992年第4期7卷 483-490页

作者： yan shuwang , yang Jinliang yan Chi Professor, Tianjin University, 300072 TianjinAssoc. Professor, Tianjin University, 300072 Tianjin Lecturer, Tianjin University, 300072 Tianjin

The results of undrained cyclic triaxial tests on three types of clays are collected and a relationship among the accumulated strain, the initial stress state, cyclic stress in the soil, as well as the number of cycles is established based on the experimental data. With this relationship, a procedure is proposed for subsidence and stability analysis on soft clay under the action of cyclic loads.

关键词： soft clay cyclic loading triaxial test accumulated strain cyclic stress

Stability Analysis of Bohai Oil-Drilling Ship No. 6 Under Static and Cyclic Loads

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China Ocean Engineering 1996年第4期11卷 465-472页

作者： Qiu Changlin yan shuwang Graduate student, Dept. of Hydraulic Engrg., Tianjin University . Professor, Dept. of Hydraulic Engrg., Tianjin University Dept. of Hydraulic Engrg. Tianjin University

This paper presents a procedure to calculate the safety factor against sliding of a marine gravity structure subjected to a combination of static and cyclic loads. This procedure claculates the stress at the sliding surface by the finite element method (FEM) and takes the dynamic properties of clay into account. With this procedure, the stability of a Bohai oil-drilling ship is analyzed. The calculated safety factor is much smaller than 1, indicating that this oil-drilling ship would fail just as what had happened to it.

关键词： oil-drilling ship stability analysis safety factor static and cyclic loads

采用强夯置换墩加固湿地中高速公路路基的研究

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岩石力学与工程学报 2009年第A1期28卷 2966-2972页

作者：董伟闫澍旺冯守中闫福生天津大学建筑工程学院天津300072 河北大唐国际唐山热电有限责任公司河北唐山063000

海拉尔至满洲里一级公路部分路线穿越海拉尔河漫滩湿地,软土层位于地表,厚度较薄,而且地下水位较高。综合考虑施工难易以及经济效益,提出强夯置换墩复合地基的设计方案,采用在夯坑内回填块石、碎石等粗颗料材料,形成大直径置换墩(桩)作... 详细信息

海拉尔至满洲里一级公路部分路线穿越海拉尔河漫滩湿地,软土层位于地表,厚度较薄,而且地下水位较高。综合考虑施工难易以及经济效益,提出强夯置换墩复合地基的设计方案,采用在夯坑内回填块石、碎石等粗颗料材料,形成大直径置换墩(桩)作为复合地基的骨架。强夯置换法是一种经济、简单易行的地基处理方法,但目前仍没有成熟的设计计算方法,施工前必须进行试夯以确定其适用性及加固效果。为此,进行了有限元分析,研究相同置换率条件下,桩(墩)径对加固效果的影响,为桩(墩)径的选择提供参考依据。通过试验区的试夯试验,确定施工参数,验证强夯置换法用于这类湿地地基的合理性。

关键词：土力学强夯置换墩法湿地高速公路桩(墩)径有限元法

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天津港南疆吹泥围埝工程试验段的试验研究

土木工程学报 2005年第1期38卷 105-109,120页

作者：刘润闫澍旺天津大学建工学院

对天津港南疆 1#靠船墩改建吹泥围埝工程的施工方案及可行性展开了深入的探讨 ,进行了一系列室内常规试验、编织袋填充模拟试验、离心机模型试验 ,对施工过程中编织袋的形状和可能受到的最大应力进行了分析验算。研究结果表明 ,只有塑... 详细信息

对天津港南疆 1#靠船墩改建吹泥围埝工程的施工方案及可行性展开了深入的探讨 ,进行了一系列室内常规试验、编织袋填充模拟试验、离心机模型试验 ,对施工过程中编织袋的形状和可能受到的最大应力进行了分析验算。研究结果表明 ,只有塑性指数小于 10的粉土才适用于吹泥围埝的施工方案 ,土工编织袋受到的最大拉应力小于其抗拉强度 ,建成围埝的整体稳定性满足要求。

关键词：围埝袋装土塑性指数水力充填离心模型试验整体稳定性