既有铁路隧道与上部建筑物相互作用及稳定性分析

襄渝铁路新人和场隧道相临重庆市某新建小区建筑岩体地基,本文采用地层结构法和结构荷载法两种技术手段,对拟建建筑和既有铁路隧道的相互影响及其稳定性进行综合分析与评价,全面分析了修建高层建筑对既有隧道围岩位移和其安全系数产生的附加影响,提出必须采取相应的措施以减小该工程的修建对地下洞室的安全和围岩稳定性的影响。     

山地城市地下空间综合节地技术示范及研究

节地是地下空间开发利用的重要目的之一,如何合理地利用地下空间是地下空间开发利用的主要研究内容。根据重庆山地城市特点,将城市公共交通、轻轨系统、商业街统一规划,提出山地城市地下空间综合节地技术,并应用于南坪交通枢纽项目,具有重要的借鉴和参考价值。     

Active vibration control for nonlinear vehicle suspension with actuator delay via I/O feedback linearization

The problem of nonlinear vibration control for active vehicle suspension systems with actuator delay is considered. Through feedback linearization, the open-loop nonlinearity is eliminated by the feedback nonlinear term. Based on the finite spectrum assignment, the quarter-car suspension system with actuator delay is converted into an equivalent delay-free one. The nonlinear control includes a linear feedback term, a feedforward compensator, and a control memory term, which can be derived from a Riccati equation and a Sylvester equation, so that the effects produced by the road disturbances and the actuator delay are compensated, respectively. A predictor is designed to implement the predictive state in the designed control. Moreover, a reduced-order observer is constructed to solve its physical unrealisability problem. The stability proofs for the zero dynamics and the closed-loop system are provided. Numerical simulations illustrate the effectiveness and the simplicity of the designed control.