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《科技通报》2016,(11)
针对水电水利工程施工中进水口岩质边坡一直存在稳定性差的问题。提出利用极限平衡法对岩质边坡进行安全设计,建立有限元模型对设计的边坡稳定性进行分析。首先,运用极限平衡法中的普遍极限平衡法计算岩体面局部稳定性,在受到外力作用情况下,求解出失稳状态值及临界滑动状态值,设计出安全的力平衡参数;然后,利用有限元模型数值模拟并计算施工开挖过程及运行期的岩体应力分布和变形规律,得出进水口边坡达到安全状态后的稳定系数。仿真实验证明,利用极限平衡法对水电站进水口岩体边坡进行安全设计,通过有限元模型对影响边坡稳定性进行分析,使边坡的安全性达到了平衡状态,为整个水利工程建筑提供了数据支持。 相似文献
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张保财 《大科技．科学之谜》2014,(3):223-224
在工程建设过程中,边坡工程是最重要的建设项目之一。为了提高非均质边坡工程质量,常常需要对非均质边坡的稳定性进行分析,对于提高边坡工程质量具有重要的影响。本文主要提出针对非均质边坡的“多级次”评价方法,该方法以强度折减理论为基础,首先对岩土体进行多次局部强度折减,得到边坡不同深度、不同岩层控制的多级潜在滑动面;然后运用极限平衡法进行各个潜在滑动面的稳定性计算,即可得到边坡不同深度、不同级次的稳定性系数。在确定多级滑动面的过程中充分利用了强度折减法客观性的优点,避开了极限平衡方法主观性的缺点,折减所得滑动面更能反映边坡在重力作用下的变形破坏过程,优于滑弧法搜索结果。通过规则模型的验证及实际边坡的应用,证明这种方法对于综合评价非均质边坡的稳定状态是有效的,并可为边坡的治理、监测设计及施工提供指导。 相似文献
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滑坡稳定性的分析方法主要有：愈陛分析方法、定量分析方法（数学模型法）、不确定性分析方法、确定性与不确定性方法的结合、物理模拟法方氘数学模型的分析方法可以分为两大类：非确超胜方法与确匙胜方法。前者主要包括模糊数学分析法、灰色理论分析法、灰色模糊综合法以及概率分析法等;后者主要包括解析法和数值分析法。其中解析法主要是基于极限平衡理论的刚体极限平衡分析法。 相似文献
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根据对现场钻探结果、原位测试、室内岩石力学试验成果以及水文地质和抗震设计条件的综合分析,采用刚体极限平衡法来计算与评价边坡的稳定性,对岩体边坡整体上是稳定的结论,为维护边坡的稳定性提出了一些建议,可供今后岩体边坡工程勘察参考。 相似文献
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边坡稳定性分析是岩土工程界的一个重要研究内容,其分析方法众多,具体有极限平衡法,数值分析法以及可靠度方法,模糊数学,神经网络等理论,本文对众多研究方法从理论基础,优缺点及其适用条件以及最近研究成果等方面做了简单介绍。 相似文献
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以某建筑边坡为例,采用极限平衡法及工程地质类比法对其稳定性进行了计算分析和预测评价,并采用"预应力锚索+挡土板+排水工程"组合措施进行了治理工程设计。 相似文献
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In this paper, a sliding mode controller (SMC) is proposed for control of a wheeled inverted pendulum (WIP) system, which consists of a pendulum and two wheels in parallel. The control objective is to use only one actuator to perform setpoint control of the wheels while balance the pendulum around the upright position, which is an unstable equilibrium. When designing the SMC for the WIP system, various uncertainties are taken into consideration, including matched uncertainties such as the joint friction, and unmatched uncertainties such as the ground friction, payload variation, or road slope. The SMC proposed is capable of handling system uncertainties and applicable to general underactuated systems with or without input coupling. For switching surface design, the selection of the switching surface coefficients is in general a sophisticated design issue because those coefficients are nonaffine in the sliding manifold. In this work, the switching surface design is transformed into a linear controller design, which is simple and systematic. By virtue of the systematic design, various linear control techniques, such as linear quadratic regulator (LQR) or linear matrix inequality (LMI), can be incorporated in the switching surface design to achieve optimality or robustness for the sliding manifold. To further improve the WIP responses, the design of reference signals is addressed. The reference position for the pendulum is adjusted according to the actual equilibrium of the pendulum, which depends on the size of the friction and slope angle of the traveling surface. A smooth reference trajectory for the setpoint of the wheel is applied to avoid abrupt jumps in the system responses, meanwhile the reaching time of the switching surface can be reduced. The effectiveness of the SMC is validated using intensive simulations and experiment testings. 相似文献
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Zhihuan Chen Xiaohui Yuan Xiaotao Wu Yanbin Yuan Xiaohui Lei 《Journal of The Franklin Institute》2019,356(15):8366-8387
This paper investigates the frequency change problem of hydraulic turbine regulating system based on terminal sliding mode control method. By introducing a novel terminal sliding mode surface, a global fast terminal sliding mode controller is designed for the closed loop. This controller eliminates the slow convergence problem which arises in the terminal sliding mode control when the error signal is not near the equilibrium. Meanwhile, following consideration of the error caused by the actuator dead zone, an adaptive RBF estimator based on sliding mode surface is proposed. Through the dead zone error estimation for feed-forward compensation, the composite terminal sliding mode controller has been verified to possess an excellent performance without sacrificing disturbance rejection robustness and stability. Simulations have been carried out to validate the superiority of our proposed methods in comparison with other two other kinds of sliding mode control methods and the commonly used PID and FOPID controller. It is shown that the simulation results are in good agreement with the theoretical analysis. 相似文献
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公路滑坡治理对保护人民的生命财产、保证交通畅通具有重要意义,目前治理公路高陡边坡的措施有SNS柔性防护技术、喷锚网支护技术、抗滑桩墙体系等。而抗滑桩工程则由于抗滑桩具有适应性强、特别适用于滑面较深的大型滑坡,因有滑坡稳定性和地质环境干扰小、可多桩同时施工、工期较短、抗滑能力强等多方面的突出优点成为滑坡地质灾害治理中一种主要的方法。本文将介绍某公路滑坡的治理经验,阐述了滑坡的形成原因,重点分析了滑坡的地质情况,提出了”抗滑桩＋削坡＋锚杆支护＋挡土墙＋截、排水工程”的滑坡体综合治理方案。 相似文献
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采用测斜技术，观测和分析天荒坪大溪滑坡体的位移发展规律，并与稳定性计算相结合，揭示滑动后残余边坡体的工作状态，为滑坡体研究和治理提供依据。 相似文献
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Chih-Chin Wen 《Journal of The Franklin Institute》2008,345(8):926-941
The design of an adaptive sliding mode control (SMC) scheme is proposed in this paper for stabilizing a class of dynamic systems with matched and mismatched perturbations. Two methods for designing a novel sliding surface function are introduced first. By utilizing a pseudocontrol input in the sliding surface function, one cannot only suppress the mismatched perturbations in the sliding mode, but also obtain the property of asymptotical stability. Then a sliding mode controller is designed to drive the controlled systems to the designated sliding surface in a finite time. Adaptive mechanism is also embedded in the controller as well as in the sliding surface function designed from the second method to overcome the perturbations, so that the informations of upper bound of perturbations are not required. An application of flight control and experimental results of controlling a servomotor are also given for demonstrating the applicability of the proposed control scheme. 相似文献
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《Journal of The Franklin Institute》2022,359(15):8084-8106
This paper’s primary motivation is to construct a class of novel terminal sliding-mode (TSM) control to stabilize systems rapidly with reduced chattering. To this end, a novel sliding surface, coined as practical TSM (PTSM) manifold, is designed with the help of the logarithmic hyperbolic cosine function. Since the partial flatness, i.e. the Lipschitz continuity and the practical terminal attractiveness, of the proposed PTSM manifold results in its derivative nonsingularity, the super-twisting algorithm (STA) is employed to generate its finite-time reachability with reduced chattering. Once the proposed sliding surface is established, controlled states will quickly fall into a small neighborhood of the equilibrium and then asymptotically slide to zero with a local high gain. In addition, this method is extended to solve the control problem of systems with mismatched uncertainties. Several groups of simulations verify the superiority of proposed controllers. 相似文献
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Finite-time stability involves dynamical systems whose trajectories converge to an equilibrium state in finite time. In this paper, we consider a general class of fully actuated mechanical systems described by Euler–Lagrange dynamics and the class of underactuated systems represented by mobile robot dynamics that are required to reach and maintain the desired trajectory in finite time. An approach known as the terminal sliding mode control (TSMC) involves non-smooth sliding surfaces such that, while on the sliding surface, the error states converge to the origin in finite time thus ensuring finite-time tracking. The main advantage of this control scheme is in fast converging times without excessive control effort. Such controllers are known to have singularities in some parts of the state space and, in this paper, we propose a method of partitioning the state space into two regions where the TSMC is bounded and its complement. We show that the region of bounded TSMC is invariant and design an auxiliary sliding mode controller predicated on linear smooth sliding surface for the initial conditions outside this region. Furthermore, we extend these results to address TSMC for underactuated systems characterized by the mobile robot dynamics. We demonstrate the efficacy of our approach by implementing it for a scenario when multiple dynamic agents are required to move in a fixed formation with respect to the formation leader. Finally, we validate our results experimentally using a wheeled mobile robot platform. 相似文献
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Yizhen Meng Bin Jiang Ruiyun Qi Jianwei Liu 《Journal of The Franklin Institute》2018,355(5):2067-2090
Due to the extreme large flight scale of Hypersonic Vehicle (HSV), the system inevitably possesses strong nonlinearity, coupling, fast time-variability and is also sensitive to disturbance and fault. The method of external anti-windup system combined with the terminal sliding mode control law (TSMC) is presented for the nonlinear control problem under the restriction of control surfaces for HSV. It can realize the compensation for the control surface saturation and let the HSV smoothly track the command signals. Then, the improved sliding mode disturbance observer (ISMDO) is proposed to estimate unknown parameters and strong external disturbance as well as the unknown actuator fault. This method does not need the information of disturbance and the fault bounds and has fewer learning parameters, which makes it suitable for the real-time control. Finally, the simulation test of attitude control for the reentry HSV is conducted, and the results show the effectiveness and robustness of the proposed scheme. 相似文献
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有限元法在临水边坡设计中的应用 总被引：1，自引：0，他引：1
近年来临水边坡工程越来越多,比如河岸、水库库岸、湖岸等,且这些工程往往结合坡顶房建项目,因此在这些临水边坡设计中不仅要保证边坡安全系数达到规范要求,还要对边坡的沉降、位移值有一个预估,以保证坡顶建筑物的安全。本文结合实际工程,采用MIDAS/GTS有限元软件分析了临水边坡在不利工况下加固前后的安全系数及位移值,并与极限平衡稳定算法的结果进行对比,较好地满足了该类实际工程对沉降及位移需要提前预判的要求,对类似工程的设计具有一定的借鉴意义。 相似文献