激光焊接技术在载货车驾驶室顶盖柔性制造中的应用研究

将激光焊接技术应用在载货车驾驶室试制中的柔性制造，利用进口的三维五轴CO2激光加工机成功地完成了大型三维驾驶室顶盖激光对接焊，试制的顶盖完全达到产品图纸要求。研制了顶盖激光切割、焊接专用夹具，并针对车身常用裸板和镀锌钢板进行了工艺试验。     

相继增压系统对改善船用直列八缸发动机性能的试验研究

随着大型柴油发动机经济性和排放要求的不断提升,以及对发动机稳态、瞬态特性要求的不断提高,传统的涡轮增压系统已无法满足船用发动机全工况性能的要求。为了提高产品竞争力和适配性,针对某8缸直列船用柴油发动机开发了带有定压排气管的相继增压系统,并进行了发动机台架试验研究。结果表明：发动机中、低转速时,相继增压系统使发动机比油耗可以下降5%-10%,排气温度降低30%-45%,烟度下降55%-60%；最大扭矩可以提升15.1%-36.4%；发动机最大扭矩转速工况突加突卸响应性提升约28%-29%；相继增压系统中定压排气管的设计使得发动机高工况性能也有所提升,从而实现发动机全工况性能的提升。     

抗滑桩在滑坡处理中的应用

结合某国道滑坡情况,根据其具体的工程地质和水文情况,提出了采用抗滑桩的处理方案。根据滑坡推力计算,确定抗滑桩的尺寸及位置,提出了施工过程动态监测和完工后长期监测的方案。     

硬岩顶管卡滞原因分析及脱困技术研究

针对长距离岩石地层顶管施工中预制管卡滞工程难题,结合观景口水利工程2#无压洞工程,通过资料查阅、案例调研、专家咨询等方法,对多种处理方案进行对比分析。结合工程实践,提出预制管受困点判别方法,并研究制定出沉渣冲洗清理及预制管拆除方案;结合顶管施工特点就如何预防预制管卡滞提出针对性改进措施。经工程验证,所采取方案与技术措施顺利解决了预制管卡滞难题,并确保了后期工程的顺利进行,既缩短了工期又取得了良好的经济效益.,可为类似工程提供借鉴和参考。     

Buckle propagation of damaged SHCC sandwich pipes: Experimental tests and numerical simulation

Sandwich pipe (SP) combining high-strength performance and thermal insulation has been considered an effective solution for oil and gas transportation in ultra-deepwater. Strain hardening cementitious composite (SHCC) is well known for its capacity to withstand both tensile load and external hydrostatic pressure. The sandwich pipe considered in the research is constituted of concentric steel pipes with SHCC annular layer. In the present research work, the SHCC was manufactured, and full scale sandwich pipes were assembled. Intact and damaged specimens were submitted to controlled external pressure in a hyperbaric chamber to obtain the collapse and propagation pressures, respectively. Modeling and simulation of the buckle propagation of the SPs were correlated with the experimental results. The results show that sandwich pipe with SHCC core has an excellent structural strength under high external pressure in both intact and damaged conditions. Moreover, the results also show that the interaction between the annular and the inner/outer pipes provides a significant contribution to the buckling resistance under propagation pressure.     

Hydroelastic analysis of oblique irregular waves with a pontoon-type VLFS edged with dual inclined perforated plates

The fluid-structure interaction of oblique irregular waves with a pontoon-type very large floating structure (VLFS) edged with dual horizontal/inclined perforated plates has been investigated in the context of the direct time domain modal expansion theory. For the hydroelastic analysis, the boundary element method (BEM) based on time domain Kelvin sources is implemented to establish water wave model including the viscous effect of the perforated plates through the Darcy’s law, and the finite element method (FEM) is adopted for solving the deflections of the VLFS modeled as an equivalent Mindlin thick plate. In order to enhance the computing efficiency, the interpolation-tabulation scheme is applied to assess rapidly and accurately the free-surface Green function and its partial derivatives in finite water depth, and the boundary integral equation of a half or quarter VLFS model is further established taking advantage of symmetry of flow field and structure. Also, the numerical solutions are validated against a series of experimental tests. In the comparison, the empirical relationship between the actual porosity and porous parameter is successfully applied. Numerical solutions and model tests are executed to determine the hydroelastic response characteristics of VLFS with an attached anti-motion device. This study examines the effects of porosity, submerged depth, inclined angle and gap distance of such dual perforated anti-motion plates on the hydroelastic response to provide information regarding the optimal design. The effects of oblique wave angle on the performance of anti-motion and hydroelastic behavior of VLFS are also emphatically examined.     

海上风电大直径单桩基础固有频率影响因素的数值分析

针对海上风电整机结构其低阶固有频率的控制问题,基于有限元分析技术开展小直径桩土相互作用的数值模拟分析,与试验结果、API规范计算结果进行对比,验证了数值模型的适用性,分析大直径单桩结构桩内土芯、冲刷深度、表层土置换措施对整机固有频率的影响,结果表明,基于有限元实体单元计算所得一、二阶整机固有频率要明显大于传统p-y方法计算结果;桩内土芯对一、二阶整机固有频率影响很小;在一定范围内,随着泥面冲刷深度的增加,一、二阶固有频率降低不明显,认为传统p-y方法对于大直径单桩的适用性有待研究;在实际工程设计中,桩内土芯的影响可忽略;对于大直径单桩,在一定范围内可以忽略冲刷的影响。     

浅埋顶管沉井周边土体的三维破坏形状及沉降研究

为研究顶管沉井及周边土体在顶进力作用下的形变范围与大小，以加固旋喷桩作为沉井周围加固体建立ABAQUS软件计算模型，并将模拟结果与工程实例、PLAXIS 3D软件所得结果进行对比分析。同时，采用广州地区花岗岩残积土进行室内沉井模型试验，并通过试验结果对数值模拟结论进行验证，得出结论如下： 1）在开挖基坑前达到设计强度的旋喷桩能有效减小基坑周边土体塌陷变形、坑底隆起。2）在施加工作顶推力下，前侧主动区首先出现贯通裂缝，竖向位移斜率增大出现明显拐点；继续增大顶推力，土体位移会急剧增大导致地表沉降严重。3）对于后背土体，在顶推力作用下，地表破裂线的切线角度从0°逐渐增大至45°+φ/2，导致破裂范围也不断扩大；达到45°+φ/2处后，继续施加顶推力会导致短轴方向破坏范围扩大的速度较长轴方向的速度更快；三维空间中被动区破坏土体在地表处产生形状为椭圆的破坏面，椭圆长轴方向为顶推轴线方向，被动破坏体呈现为牛角状椭圆楔体。     

城市大型医院周边道路交通问题剖析及改善对策——以深圳市为例

为了合理科学组织医院周边及内部交通,避免重现目前深圳大型医院周边普遍存在的交通拥堵、停车困难、进院车辆排队、的士乘坐不便等交通问题,以深圳市为例,分析现状大型医院周边存在的道路交通问题和产生原因,提出完善周边道路交通设施、大力发展公共交通、合理规划医院布局、建立科学有效的交通组织体系等改善对策.     

中国TBM施工技术进展、挑战及对策

总结我国近30年来TBM设计与施工技术的发展历程,可归纳为以下5个阶段:1)研发探索和试用阶段;2)以国外施工承包商为主体,采用国外设计制造TBM施工我国隧道工程阶段;3)独立进行TBM招标采购和选型设计,并建立起自主的TBM施工队伍阶段;4)与国外厂家联合设计制造TBM,工程应用和自主施工快速发展阶段;5)实现TBM国产化,面向国内外TBM工程市场自主施工阶段。通过我国不同时期TBM施工的典型工程,介绍我国在复杂地质、大坡度、高海拔、不同直径、不同机型、超长隧洞TBM施工方面取得的经验、技术积累和业绩,展示我国TBM在穿越断层破碎带、软弱变形、岩爆、涌水等不良地质洞段取得的一系列施工新技术,以及最高月进尺1 868 m、平均月进尺超过600 m和掘进作业利用率超过40%的掘进技术水平。分析TBM在极硬岩、大断层破碎带、软弱大变形围岩、强岩爆围岩、涌水突泥洞段、高地热隧洞和超长隧洞工程中施工面临的风险和挑战,并提出一些相应的技术措施和对策,期望这些措施和对策在未来大量实际工程中进一步得到实践验证、优化和改进,不断积累和创新TBM设计与施工新技术。