“一带一路”下中国食品贸易争端解决的法律机制

随着"一带一路"在沿线国家间的有序推进,中国食品贸易量在迅速扩大,而其中的食品贸易争端也随之逐渐凸显。由于中国食品安全保障的法制机制建立时间较晚,食品安全标准不够统一且无法与国际标准接轨,中国食品贸易因此屡遭技术性贸易壁垒。对此,应在进一步完善国内食品安全保障的法律体系基础上,调整国内食品安全标准以回应国际要求,并从主导建立涵盖"一带一路"沿线国家在内的统一食品安全质量标准、掌握食品安全保障区域规则制定的话语权,以及落实法律机制的具体实施途径等维度,对中国食品贸易争端解决的法律机制进行构建。     

特高砂砾石面板坝流变效应及面板防裂措施

针对高面板坝后期变形导致的面板破坏问题,采用大型室内试验测定了大石峡筑坝料流变力学特性,重点研究了后期流变效应对坝体、防渗体应力变形的影响。评估了各期面板浇筑前坝体沉降速率,复核了面板浇筑前预沉降时间的合理性。研究结果表明,该坝各期面板浇筑前设置的预沉降期可将坝顶沉降率控制在5mm/月以内。大坝蓄水运行后面板应力,尤其是轴向应力,较初次蓄水增加明显,存在挤压破坏的风险。论证了在面板受压区设置柔性缝的面板应力改善措施,结果表明该工程措施对削减面板轴向压应力效果明显。总体上,250m级的特高砂砾石面板坝坝体和防渗体应力变形能满足安全控制要求,通过合理的工程措施可保证大坝施工与运行安全。     

Multi-objective optimization of shield construction parameters based on random forests and NSGA-II

Metro shield construction will inevitably cause changes in the stress and strain state of the surrounding soil, resulting in stratum deformation and surface settlement (SS), which will seriously endanger the safety of nearby buildings, roads and underground pipe networks. Therefore, in the design and construction stage, optimizing the shield construction parameters (SCP) is the key to reducing the SS rate and increasing the safe driving speed (DS). However, optimization of existing SCP are challenged by the need to construct a unified multiobjective model for optimization that are efficient, convenient, and widely applicable. This paper innovatively proposes a hybrid intelligence framework that combines random forest (RF) and non-dominant classification genetic algorithm II (NSGA-II), which overcomes the shortcomings of time-consuming and high cost for the establishment and verification of traditional prediction models. First, RF is used to rank the importance of 10 influencing factors, and the nonlinear mapping relationship between the main SCP and the two objectives is constructed as the fitness function of the NSGA-II algorithm. Second, a multiobjective optimization framework for RF-NSGA-II is established, based on which the optimal Pareto front is calculated, and reasonable optimized control ranges for the SCP are obtained. Finally, a case study in the Wuhan Rail Transit Line 6 project is examined. The results show that the SS is reduced by 12.5% and the DS is increased by 2.5% with the proposed framework. Meanwhile, the prediction results are compared with the back-propagation neural network (BPNN), support vector machine (SVM), and gradient boosting decision tree (GBDT). The findings indicate that the RF-NSGA-II framework can not only meet the requirements of SS and DS calculation, but also used as a support tool for real-time optimization and control of SCP.     

Collineation measurement: A method for constructing the imperial citadel of Thang Long in harmony with nature

The Imperial Citadel of Thang Long is a crucial case in ancient Vietnam’s planning and design history. Although historical materials indicate that the orientation of the Imperial Citadel of Thang Long has a dialectical unity relationship with the surroundingmountains, current research is only speculative generalization and lacks empirical analysis. Based on existing findings, this paper identifies the collineation measurement as a generalmethod in the Sinosphere countries for determining spatial orientation. Using a mixed-method of historical archives, fieldwork and simulation model, this paper summarizeshistorical cluesandthreedesignperspectives related to spatial orientation by statistical analysis. Further, it analyzes the logic and application of collineation measurement in constructing the Imperial Citadel of Thang Long. The results show that Vietnamese designers used Tàn Viên Mountain as a component of Thang Long city by collineating the twomountain peaks to the west. Tàn Viên Mountain and the highlands extending eastward fromit are used as the key to establishing the position of the Imperial Citadel, setting the spatial structure of human settlements, and the development of city space. The location, layout, and formof important buildings in the Imperial Citadel are also closely related to the surrounding landscape within 50 km.     

球罐基础沉降差对支柱稳定性影响的分析处理

介绍了球罐安装中可能出现的球罐支柱失稳问题。对1台5000 m3球罐的基础沉降差对支柱稳定性的影响进行了计算分析,并提出了一些增强球罐支柱稳定性的措施。     

Tunnelling-induced response of a jointed pipeline and its equivalence to a continuous structure

The response of a jointed pipeline to tunnelling-induced ground settlement relies largely on the soil-pipe interaction. An analytical solution incorporating the Pasternak model is formulated here to estimate a jointed pipeline's deflection and bending moment. Subsequently, a procedure is proposed to transform the jointed pipeline to an equivalent continuous structure for a deflection evaluation. Case studies are conducted to verify the analytical solution, followed by parametric studies to assess the effects of the Pasternak model's parameters and the pipe joints. The analytical solution is validated by the experimental results in the literature. The parametric studies show that the number and distribution of the joints have a mild effect on the pipe deflection, whereas their influence on the pipe bending moment is significant. Similarly, the pipe bending moment is more sensitive than the pipe deflection to subgrade shear stiffness.     

厦门地铁车站基坑施工诱发地表沉降的经验#br# 预测方法研究

地铁建设的快速发展对于缓解国内大中城市的交通拥堵问题具有极其重要的意义,然而,轨道交通运营线路多通过城市的主要街区以及繁华商圈,车站周边地表受基坑开挖影响产生沉降等环境问题较为显著,须在支护设计阶段对其进行有效地预测及控制,以便最大程度地降低施工阶段发生工程灾害的机率。基于厦门地铁1号线车站建设过程中邻域地表沉降的监测数据,对实测沉降槽曲线进行归一化处理和统计分析,得出适用于厦门地区类似工程条件下地铁车站基坑施工诱发周边地表沉降的经验预测方法,为后续的地铁建设提供参考建议。