Property Evolution of Sulphoaluminate Grouting Material under Pressure Circulation北大核心CSCD

Water-sealed underground oil tank projects are quite different from traditional underground projects since the water-sealing conditions are very strict and the difficulties caused by the geological specificity, structural specificity and construction specificity are key factors affecting the project. In light of the significant early initial setting time and rapid temperature increase of sulphoaluminate cement-based grouting material for a large domestic water-sealed underground oil tank with pressurized cyclic grouting, a laboratory grouting simulation is conducted. It is found that the properties of the sulphoaluminate cement-based grouting material are quite different under different pressure cycles, the hydration exothermic peak time gets shorter with an increase of circulation time, the compressive strength decreases with an increase of circulation time, and the longer the circulation time the more obvious the de-crease of compressive strength. © 2018, Editorial Office of "Modern Tunnelling Technology". All right reserved.     

Model Test on Grouting Law in Dynamic Water-Rich Sand Layers by the Electric Resistance Method北大核心CSCD

In order to study the diffusion law of grouting slurry in the water-rich sand layer under flowing water conditions, a grouting test model consisting of a main test system, a grouting system, and a measurement system was developed. And for detecting the diffusion scope of the grouts, a new resistivity method was proposed. It is found that the relationship between grouting pressure and grouting rate during the test is strong. Under hydrodynamic conditions, the grouting slurry diffuses elliptically. Due to gravity and the effect of the upper water flow, the center of gravity of the ellipsoid is below the grouting outlet, and the grouting effectively improves the physical and mechanical properties of water-rich sand bodies. At the same time, the resistivity method has a good application effect on the detection of grouting diffusion range. The range of slurry diffusion obtained by the resistivity method is basically consistent with the boundary of the stone body after excavation, indicating that the resistivity method is reliable for detection of grouting range in dynamic water-rich sand layer. © 2018, Editorial Office of "Modern Tunnelling Technology". All right reserved.     

Effect of Seismic Parameters on the Safety Factor for an Underground Cavern北大核心CSCD

In order to quantitatively evaluate the safety of the surrounding rock of an underground cavern under seis-mic load, a comprehensive evaluation method for the stability of surrounding rock is proposed based on the general safety factor and point safety factor. A calculation method for the general safety factor of a cavern based on the prin-ciple of shear strength reduction of a rock mass is given, the run-through of the plastic zone between the main power-house and main transformer room is presented as a critical criterion for the overall instability of the cavern, and the general safety factor is obtained by searching for the reduction coefficient. A point safety factor calculation method based on the Mohr-Coulomb yield criterion is given. The influence of different seismic input parameters on the general safety factor of the cavern and the point safety factor of key positions are studied based on an underground power-house cavern of a hydropower station in Southwest China. The results show that the quantitative evaluation method for the stability of the surrounding rock based on the safety factor is feasible and can reflect the general safety de-gree and local safety degree of different positions of the cavern for different working conditions. It is found that the general safety factor of the cavern and the point safety factor of key positions decrease with an increase of the ampli-tude and duration of a seismic wave while they increase with an increase of the incident angle; additionally, the low frequency of a seismic wave has a great influence on the cavern while the high frequency has little effect. © 2018, Editorial Office of "Modern Tunnelling Technology". All right reserved.     

Analysis on the Effects of Overloading on the Mechanical Properties of Tunnel Structures in the Silty Ground --A Case Study of Sutong River-crossing GIL Utility Tunnel北大核心CSCD

Based on the Sutong GIL utility tunnel project, which is constructed by the shield machine under the river, and as for the overloading problem at the river bank slope during operating period, the refined threedimensional finite element model was established to study the deformation and cracking characteristics of the tunnel segment structure under different forms of overloading. The evolution laws of section convergence, joint opening and structural stress were analyzed, and the structure damage mechanisms were revealed under conditions of large area loading and local loading. The surface-surcharge control standard was proposed. For the big diameter shield tunneling crossing the silty clay, the research results show that: (1) the deformation failure process is divided into three stages under large area loading condition, taking the design load and compressive yield of rebars inside haunch as the critical points respectively. The first stage is characterized by the elastic stress, the second stage is in plastic state with fracture, and the third stage is accelerating deformation and instability stage. The vertical convergence is 110.5 mm with no opening of joints when rebars are yielded; (2)the deformation failure process under local loading condition is also divided into elasticity, plasticity and instability stages, taking the design load and tensile yield of rebars outside haunch as the critical points respectively. The vertical convergence is 152.6 mm with joint opening of 4.36 mm; (3) the early-warning values of additional stress on the ground under conditions of large area loading and local loading are 110 kPa and 70 kPa respectively. © 2018, Editorial Office of "Modern Tunnelling Technology". All right reserved.     

基于石墨烯的柔性薄膜电极进展

石墨烯具有诸多优异的物理、化学特性,在电化学储能领域得到了广泛的关注。本文综述了石墨烯薄膜以及石墨烯复合材料薄膜在锂离子电池以及超级电容器柔性电极中的应用进展。根据石墨烯在柔性电极中作用的不同分为三个部分结合研究实例分别论述,并对石墨烯基薄膜电极材料在柔性电化学储能器件中的应用前景进行了分析和展望。     

吸盘式挖泥船全电力驱动系统设计

本文根据某吸盘式挖泥船的使用要求,设计了全电力驱动系统方案。对配电系统方案、变频驱动系统方案和谐波处理方案进行了详细分析。与当前典型的挖泥船变频驱动系统方案相比,本文提出了一种新的更加经济的系统方案,并在实船已成功应用。     

海缆供电导体阳极电化学腐蚀特性研究

为了延长海底受损光电缆的最大供电时间,分析了海缆导电芯线在海洋环境中的电腐蚀特性的影响,模拟海洋环境设计实验对比了三种不同规格海缆在不同受损程度下的电腐蚀特性以及最大供电时间。此外,本文还探究了钛合金材料对于改善受损海缆电化学腐蚀特性的应用前景。实验结果表明可以通过改善设计,使用新材料等手段有效延长供电时间。     

基于WSN的电力推进船舶电气设备过热监测系统研制

针对目前电力推进船舶普遍采用有线进行电气设备过热监测的局限性,结合无线传感器网络(WSN)技术,研制了一种基于WSN的电力推进船舶电气设备过热监测系统。设计并制作了中心节点和传感器节点的硬件,编写了过热监测的软件并创新性的采用软件动态休眠节能和发射功率控制的方案,有效的延长了系统的使用寿命。结果表明该系统实现了电气设备过热的精确测量,实验室数据测试证明其和有线测量可以达到同样的精度。     

全固态锂离子电池的研究进展

本文着重介绍了固态电解质的特性,包括聚合物电解质、氧化物电解质、硫化物电解质;分析了固态电池的应用现状,指出了固态锂电池技术未来的发展趋势。     

舰船静力学性能考核评价指标及考核能力需求初探

从舰船静力学性能的原理出发,总结现有水面舰船浮性、稳性、不沉性考核标准,开展舰艇平台浮性、稳性、不沉性考核方法研究,对现有考核方法进行归纳梳理,分析考核典型舰船平台静水力学性能的基本能力要求,提出靶场考核装备建设需求,对拓展靶场职能使命,提升新形势下靶场试验考核能力具有实际的意义。