西安地铁隧道中隔墙加台阶法施工诱发的邻近桥桩变形及其控制措施

采用FLAC3D软件预测了地铁中隔墙加台阶法施工诱发的邻近桥桩变形规律,结果表明:桥桩最大水平变形和倾斜率均超出变形允许值,必须对既有桥桩采取加固措施才能确保其在地铁施工期间的安全使用。提出了采用袖阀管注浆技术控制桥桩变形的措施,并制定了现场监测方案。实测结果表明,加固措施能够确保桥桩变形在允许范围内,证明了提出的变形控制措施合理有效。     

Flow-field guided steering control for rigid autonomous ground vehicles in low-speed manoeuvring

ABSTRACT

This paper studies the low-speed manoeuvring problem for autono-mous ground vehicles operating in complex static environments. Making use of the intrinsic property of a fluid to naturally find its way to an outflow destination, a novel guidance method is proposed. In this approach, a reference flow field is calculated numerically through Computational Fluid Dynamics, based on which both the reference path topology and the steering reference to achieve the path are derived in a single process. Steering control considers three constraints: obstacle and boundary avoidance, rigidity of the vehicle, plus the non-holonomic velocity constraints due to the steering system. The influences of the parameters used during the flow field simulation and the control algorithm are discussed through numerical cases. A divergency field is defined to evaluate the quality of the flow field in guiding the vehicle. This is used to identify any problematic branching features of the flow, and control is adapted in the neighbourhood of such branching features to resolve possible ambiguities in the control reference. Results demonstrate the effectiveness of the method in finding smooth and feasible motion paths, even in complex environments.     

基于客票数据的城市轨道交通车站客流控制决策研究

城市轨道交通大客流控制是保证运行秩序和乘客安全的客运组织管控手段,目前由运营人员根据经验进行大客流辨识和客流控制决策的模式具有一定的主观性和滞后性。基于自动售检票系统(AFC)历史客票数据,分析车站大客流的发展规律,基于实时客票数据和列车运行实绩,获取进站客流的实时聚集数量及其空间分布情况,提出的辅助决策方法能够基于客票数据确定车站客流控制等级和控制时机,具备较好的精确性和前瞻性。     

高温条件下梁体预制混凝土施工质量控制措施

结合工程项目实例，对炎热夏季高温条件下混凝土的施工特点进行了分析，制定了有针对性的梁体预制混凝土施工的质量控制措施，并通过实施取得了较好的效果。     

钢网面板加筋土挡墙动力特性试验的变形研究

基于泥质红砂岩粗粒土填料，采用MTS分别模拟地震荷载、交通荷载、加-卸载多循环荷载进行大尺寸模型试验，研究了钢网面板土工格栅加筋土挡墙在上述荷载作用下的动力特性，获得了不同峰值的水平地震激励下模型挡墙不同位置的水平动位移、竖向动位移峰值响应等实测值；采用不同频率、不同幅值的竖向交通荷载正交试验法，获得了该模型挡墙在重复荷载作用下的最大水平变形、最大沉降量及位置等动力特性参数值；通过7种荷载、21组加卸载循环试验，获得了加一卸载多循环荷载作用下的实测沉降值。试验结果表明：该加筋结构具有整体变形的特性，是优良的抗震结构，能承受抗震设防烈度为9度的地震荷载；同时该加筋结构具有良好的稳定性和抗破坏性，重复荷载的幅值和振动次数对结构动力变形特性的影响较大，而振动频率对变形特性的影响不显著；多循环荷载作用下该加筋结构能够明显减小不均匀沉降。过长的筋材并不能明显地改善加筋土挡墙的动力特性。     

暗挖车站跨既有隧道施工技术

针对洞桩法暗挖车站跨既有隧道施工项目,通过增加施工通道,采用门式钢架加固等创新、改良工艺,解决了施工工序转换的难题,节约工程成本,降低施工风险。     

基于DYNAware的车辆稳定性控制仿真研究

使用车辆动力学仿真软件DYNAware／ve—DYNA，建立15自由度的参数化车辆模型，基于稳定性控制原理，以横摆角速度和质心侧偏角为控制变量，采用改进的横摆力矩决策计算方法，用Matlab／simulink建立控制器模型，并通过界面将其导入Ve—DYNA中。最后通过双移线和正弦延迟仿真实验验证了控制策略的有效性。     

Observer-based clutch disengagement control during gear shift process of automated manual transmission

A clutch disengagement strategy is proposed for the shift control of automated manual transmissions. The control strategy is based on a drive shaft torque observer. With the estimated drive shaft torque, the clutch can be disengaged as fast as possible without large driveline oscillations, which contributes to the reduction of total shift time and shift shock. The proposed control strategy is tested on a complete powertrain simulation model. It is verified that the system is robust to the variations of driving conditions, such as vehicle mass and road grade. It is also demonstrated that the revised system with switched gain can provide satisfactory performance even under large estimation error of the engine torque.     

浮式平台与钢吊箱相结合技术在忠县长江公路大桥基础施工中的应用

忠县长江公路大桥11号主墩基础施工采用浮式平台与钢吊箱相结合的方法,施工技术新颖,工序转换快捷、安全。介绍其具体施工情况。