冻胀状态下盾构隧道匝道非开挖连接最优曲线探究

基于采用主线与匝道盾构间设置横向管幕与冻结法相结合，构筑新的结构来建造两者间分合流段。为了寻求较为合理的曲线连接，首先假定在无弯矩的理想状态下推导出相应的平衡方程，并考察在冻胀情况下判断出最优曲线的轨迹应为圆弧。最后依托上海市北横通道工程实际，选择上下匝道出主线的方案建立最优曲线方程，为结构整体受力分析打下基础。     

北京东坝车辆段上盖道路对外衔接方式研究

北京东坝车辆段位于东坝西区北边界，车辆段采用地面形式布置，二层为上盖综合开发，车辆段北侧紧邻规划快速路。根据交通分析区域内约70%机动车对外交通需通过车辆段上盖道路进入北侧快速路系统，其中约45%为上盖开发内部产生，上盖道路则兼顾区域过境和上盖物业集散双重功能。因此，上盖道路与快速路系统的高效衔接为研究重点。结合主要交通需求和周边规划路网布局分析后，明确了上盖道路的交通功能。在此基础上列举了多种上盖路与快速路系统的衔接方式，并利用交通仿真分析进行比较。最终推荐方案可同时满足区域过境和上盖物业集散与快速路衔接的交通组织特点，可最大限度提升区域交通运行效率。     

Design and model test of a soft-connected lattice-structured floating solar photovoltaic concept for harsh offshore conditions

Various types of floating solar photovoltaic (FPV) devices have been previously proposed, designed and constructed with applications primarily limited to onshore water bodies or near-shore regions with benign environmental conditions. This paper proposes a novel FPV concept which can survive harsh environmental conditions with extreme wave heights above 10 m. This concept uses standardised lightweight semi-submersible floats made of circular materials as individual modules. The floating modules are soft connected with ropes to form an FPV array. We first present the conceptual design of the floats and the connection systems, including hydrostatic, hydrodynamic, and structural assessments of the floats. To verify the motion response performance, we carried out 1:60 scaled model tests for a 2 by 3 array under regular and irregular wave conditions. From the time series and response spectra, the motion characteristics of the array and the mooring responses are analysed in detail. The proposed concept exhibits excellent performances in terms of modular motions with limited wave overtopping and no contact is observed between adjacent modules under the extreme wave conditions. The findings of this study can serve as a valuable reference to developing reliable and cost-effective FPV technologies for offshore conditions.     

上海普通干线公路与城市道路网衔接规划设计策略研究

随着上海市域外围新城、主城扩区和新市镇的发展，城乡之间的界限日趋模糊，在出行特征、出行质量要求等方面，城乡结合地区的居民与城市居民之间的差异日趋缩小，部分普通干线公路已经无法满足日益增长的城镇化交通出行需求。在新的国土空间规划及建设用地总量严控背景下，上海市城郊区域亟需优化普通干线公路与城市道路的衔接融合模式。通过梳理上海普通干线公路与城市道路的衔接现状，以问题为导向，聚焦现状衔接点位置不适宜、衔接点前后设施设计不匹配等问题，根据上海不同分区的交通特征，从布局衔接、功能衔接、标准衔接等方面讨论了普通干线公路与城市道路衔接的设计要求。     

Fatigue tests on grouted connection segment specimens in offshore wind turbine structures considering water ingression

Grouted connections (GCs) are widely used to connect superstructures and driven piles in offshore wind turbine structures. They resist fatigue loading in marine splash zones and even submerged environments. In this paper, six GC segment specimens were designed and tested under fatigue loading in both the air and water ingression conditions. The results in the air condition showed that for the specimens with lower loading ranges, the strain distributions and residual displacements stabilized after 20 thousand load cycles. These conditions persisted until the end of the test with two million cycles, with only a few tiny cracks appearing on the grout material surface. Meanwhile, wide cracks and grout material exfoliation were found in specimens with higher loading ranges. The residual displacement accumulated gradually, which eventually caused the termination of the test when it reached 5 mm after 1.3 million cycles. The results in the water ingression condition showed that the water had entered into the micro-cracks of the grout material, which severely degraded the fatigue behavior of the GC specimens. Even in lower loading ranges, specimens W-1 and W-2 only endured 0.264 million and 64 thousand load cycles before the displacement of the top clamp reached −10 mm. Compared with two specimens tested in the air, with a total displacement of less than −0.7 mm after two million load cycles, the severe deteriorating effect of water ingression on the fatigue behavior of GCs was apparent.