【作者】 刘宣宇；

【导师】 邵诚；

【作者基本信息】 大连理工大学 ， 控制理论与控制工程， 2012， 博士

【摘要】 土压平衡盾构机是一种地下工程施工中的专用工程机械,广泛应用于地铁隧道、市政建设、资源开采、水利工程等地下工程建设。盾构掘进施工首先要考虑的是地表沉降控制,而盾构密封舱压力失衡是地表沉降甚至灾难性事故发生的主要成因。由于地质条件的随机多样性与多场耦合作用使得掘进界面的物理和力学行为极为复杂、难以预测,并且现有的土压平衡控制技术主要是凭经验人工操作,掘进施工的安全性难以得到保证。因此,多场耦合作用下密封舱土压动态平衡控制是盾构技术研究中重要课题。本文在对盾构掘进过程进行机理分析的基础上,结合先进控制理论与优化算法,对盾构机密封舱压力场分布、土压控制模型及协调控制等与密封舱压力平衡控制相关的理论进行了研究,论文的主要工作如下：(1)研究了掘进过程密封舱压力场的分布规律及压力失衡的特征,提出了基于密封舱压力场梯度的开挖面稳定性判定方法。利用非均匀B样条最小二乘方法建立了密封舱压力场的分布模型,在此基础上,分析了竖直与水平方向压力梯度变化,给出了基于密封舱压力场梯度范数的开挖面稳定域及判定方法,并利用多级动态惩罚函数与粒子群(PSO)相结合的优化算法求解梯度范数的极值。最后,利用现场施工数据进行了仿真研究,揭示了密封舱压力平衡、失衡时的压力分布特征,对开挖面的稳定性进行了判断,验证了方法的有效性。(2)盾构机掘进过程机理非常复杂、工况多变,目前尚没有比较精确、完善的土压平衡控制模型。为此,本文提出了采用机理分析与最小二乘支持向量机(LS-SVM)理论相结合的建模方法。首先根据盾构掘进过程的力学平衡方程、连续性方程等,以及盾构推力、推进速度、螺旋输送机转速等施工控制参数对密封舱土压的影响程度不同引入权重系数,建立了密封舱土压与掘进控制参数的关系模型；然后基于LS-SVM技术建立误差模型并求取权重系数的最优值,给出了完整的密封舱土压控制模型,为实现盾构土压平衡的自动控制奠定了基础。(3)盾构机在均一稳定的地质中掘进时,通常采用排土控制模式即调节螺旋输送机转速的方式控制密封舱土压平衡。为了有效控制整个开挖面的稳定,提出了以密封舱等效压力平衡为控制目标的土压平衡控制方法。在密封舱压力场分布模型的基础上,通过分析掘进控制参数与密封舱压力的关系,同时考虑了开挖面上压状态变化对土压的影响,建立了密封舱等效压力控制模型,构建了上压平衡控制系统,设计了模糊自适应PID控制器调节螺旋机转速。仿真结果表明系统具有对土压设定值很好的跟踪特性,为盾构掘进过程的上压平衡控制提供了新思路。(4)当盾构机在岩性变化频繁、物理力学特性差异大,尤其是复合地层中掘进时,同时调节推进速度和螺旋机转速才能更加有效的控制密封舱土压平衡。但现有的控制方法主要是依据经验人工调节推进速度或螺旋机转速,这样容易导致蛇形路线、机器故障甚至地表塌陷。为此,本文提出了一种基于最小二乘支持向量机和粒子群优化算法的土压平衡优化控制策略。采用LS-SVM建立了以推进速度和螺旋机转速为控制参数的密封舱土压预测模型,在此基础上,以密封舱下一时刻预测土压与期望土压差值最小为优化性能指标,建立了掘进控制参数的优化模型,并引入了PSO进行全局优化求解,同时优化了推进速度和螺旋机转速,实现了密封舱土压平衡控制。仿真结果验证了方法的有效性。(5)密封舱压力主要受推进、排渣和刀盘三个子系统的影响,但由于舱内碴土组分及其力学特性对密封舱压力的影响规律不清,目前施工中还难以通过推进、排渣和刀盘等多子系统综合协调来实现密封舱压力的高效平衡控制。为此,本文基于地层状态识别,提出了专家系统控制和预测控制相结合的多子系统协调控制方法。地层识别系统以扭矩切深(TPI)和场切深(FPI)为输入特征参数对地层状态进行识别,专家系统对地层识别的量化结果进行分析推理并给出刀盘转速的控制策略；然后,利用非线性模型预测控制来协调控制与刀盘转速相适应的推进速度和螺旋输送机转速,并通过改进的蚁群系统算法(ACS)进行控制参数的滚动优化。从实验结果可以看出,即使在工况发生变化时也能够很好的保持密封舱土压平衡,表明了方法的可行性,实现了盾构机土压平衡的多子系统协调控制。更多还原

【Abstract】 Earth pressure balance (EPB) shield machine is an engineering machine specialized in underground construction engineer, and is widely applied in metro tunnel, municipal construction, resources exploitation, hydraulic engineering and so on. The ground surface settlement must be taken into account first, and the earth pressure imbalance in pressure chamber is the main cause of ground settlement or even disastrous accident. The random diversity of geology condition and the multi-field coupling make the physical and mechanical properties of excavation face very complex and difficult to predict. Nowadays, the EPB control is manually operated based on experiences, so that it is difficult to ensure the construction safety. Consequently, the earth pressure balance control in chamber is an important issue of the shield construction technology. In this dissertation, some problems related to the earth pressure balance control in chamber are studied based on the mechanism analysis of tunneling process, such as modeling the earth pressure field in pressure chamber, the earth pressure balance control method, the coordinated control method of multiple sub-systems and so on. The main works of this dissertation are as follows:(1) The earth pressure distribution discipline and the earth pressure imbalance characteristic in chamber are studied, and a stability judgment method of shield excavation face is proposed based on the earth pressure field gradient. A distribution model of the earth pressure field is established by using non-uniform B spline method. On this basis, the ranges of the vertical and horizontal gradient are analyzed, subsequently, the stable region of the excavation face and the judgment method are given based on the norm of the earth pressure field gradient. For the norm extremum of the earth pressure field gradient, it is obtained through solving the optimization function by means of the multi-stage dynamic penalty function combined with particle swarm optimization (PSO) algorithm. Finally, the simulation experiment is carried out based on the field data, and the earth pressure distribution in chamber are revealed when it is balance or not, further the excavation face stability is analyzed, and the effectiveness of the method is demonstrated.(2) The mechanism of tunneling process is very complicated and the working conditions are changeable, and there is no more accurate and perfect earth pressure control model at present. A modeling method combining mechanism analysis with least squares support vector machine (LS-SVM) theory is proposed. Firstly, a relation model between earth pressure and control parameters is established based on mechanics balance equation, continuity equation and a weighting coefficient which reflects that the total thrust of shield, advance speed and screw conveyor speed have quite different influence on chamber earth pressure. Secondly, an error model is established by means of LS-SVM for optimizing the weighting coefficient, and an integrated earth pressure control model is established which lays the foundation for automatic control of EPB shield machine.(3) When shield machine excavates in homogeneous and stable soil layer, the earth pressure balance in chamber is controlled through adjusting advance speed or screw conveyor speed based on the discharge control mode. In order to control the earth pressure balance more efficiently, a new earth pressure balance control method is proposed which takes equivalent earth pressure in chamber as control target. Based on the earth pressure field model, by analyzing the relationship between tunneling control parameters and the earth pressure in chamber and considering the influence on earth pressure of the state change of earth pressure on excavation face, an equivalent earth pressure control model is established. Then, an EPB control system is constructed, in the mean time the fuzzy adaptive PID controller is designed to adjust the screw conveyor speed. The simulations illustrate that the system could track the set earth pressure very well, so that this method provides a new idea for control earth pressure balance of shield tunneling.(4) The lithology changes frequently, its physical and mechanical properties differ widely. When shield machine works under this condition, especially in composite soil layer, the earth pressure balance in chamber of shield should be controlled more efficiently by adjusting advance speed and screw conveyor speed simultaneously. But the commonly used method now depends greatly on experiences of operators, so that some problems such as meandering routes, ground subsidence, and machine failure tend to occur. For this purpose, an optimal control strategy for earth pressure balance is proposed in this paper, where an prediction model of earth pressure in chamber is established by means of LS-SVM considering thrust speed and screw conveyor speed as the control parameters. Further, by minimizing the difference between the predicted earth pressure and the desired one, an optimization model of the control parameters is established, and solved by the particle swarm optimization (PSO) algorithm. The advance speed and screw conveyor speed are optimized simultaneously, therefore, the dynamic balance control of earth pressure in chamber is realized. The simulation results demonstrate that the method is very effective.(5) The earth pressure in chamber is mainly affected by thrust system, discharge system and cutter head system. However, because it is not clear that how the composition and the mechanical characters of the soil in chamber influence the earth pressure, it is difficult to carry out earth pressure balance control efficiently through coordinated control thrust system, discharge system and cutter head system at present. For this reason, on the basis of soil layer identification, a coordinated control method of multiple subsystems is proposed which combines the expert system control with predictive control. The soil layer system identifies the layer status which takes the TPI and FPI as input character parameters. The expert system analyses and inferences to the quantitative results of the identification and gives the control strategy of cutter head. Then the advance speed and screw conveyor speed are coordinated through nonlinear model predictive control which corresponds to the cutter speed, and rolling optimization is realized by means of ACS. The experiments show that the earth pressure in chamber can keep a good balance even though the working condition changes, which demonstrate the feasibility of this method to achieve the multiple subsystems coordinated control of shield machine for earth pressure balance in chamber.更多还原