In order to exactly provide scientific basis for pressure dynamic balance control of working chamber of earth pressure balance shield (EPBS),study on optimal arrangement of pressure measurement points in working chamb...In order to exactly provide scientific basis for pressure dynamic balance control of working chamber of earth pressure balance shield (EPBS),study on optimal arrangement of pressure measurement points in working chamber was conducted. Based on mathematical description of optimal arrangement for pressure measurement points,fuzzy clustering analysis and discriminant analysis were used to divide pressure regions of nodes on bulkhead. Finally,the selection method of optimal measurement points was proposed,and by selecting d6.28 m EPBS as study object,the case study was conducted. By contrast,based on optimal arrangement scheme of pressure measurement points,through adopting weighted algorithm,the absolute error mean of equivalent pressure of working chamber is the smallest. In addition,pressure curve of optimal arrangement points presents parabola,and it can show the state of pressure distribution on bulkhead truly. It is concluded that the optimal arrangement method of pressure measurement points in working chamber is effective and feasible,and the method can provide basis for realizing high precision pressure control of EPBS.展开更多
In order to deal with modeling problem of a pressure balance system with time-delay, nonlinear, time-varying and uncertain characteristics, an intelligent modeling procedure is proposed, which is based on artificial n...In order to deal with modeling problem of a pressure balance system with time-delay, nonlinear, time-varying and uncertain characteristics, an intelligent modeling procedure is proposed, which is based on artificial neural network(ANN) and input-output data of the system during shield tunneling and can overcome the precision problem in mechanistic modeling(MM) approach. The computational results show that the training algorithm with Gauss-Newton optimization has fast convergent speed. The experimental investigation indicates that, compared with mechanistic modeling approach, intelligent modeling procedure can obviously increase the precision in both soil pressure fitting and forecasting period. The effectiveness and accuracy of proposed intelligent modeling procedure are verified in laboratory tests.展开更多
在离心泵性能数值模拟结果与试验测试结果基本吻合的基础上，对泵平衡孔直径在0-12mm 的范围内，进行泵扬程、效率和轴功率预测，研究泵设计工况下，不同平衡孔直径时，平衡腔内液体压力沿轴向、径向和切向分布规律，以及其对盖板力的...在离心泵性能数值模拟结果与试验测试结果基本吻合的基础上，对泵平衡孔直径在0-12mm 的范围内，进行泵扬程、效率和轴功率预测，研究泵设计工况下，不同平衡孔直径时，平衡腔内液体压力沿轴向、径向和切向分布规律，以及其对盖板力的影响，并绘制出pfk关系曲线。结果表明：同一流量工况时，平衡孔直径增大到一定值后，轴功率明显增大，效率显著降低，但在大于设计流量工况时，扬程与平衡孔直径无关；同一平衡孔直径下，平衡腔压力沿轴向和切向基本保持不变，压力由泵轴至密封环沿径向增大；在平衡腔内小于平衡孔圆心与泵轴中心垂直距离的半径区域，平衡孔直径越小，压力沿径向越趋近于零，而在平衡腔内大于上述半径区域，平衡孔直径越大，压力沿切向越大；比面积 k ≥2.645时，平衡腔区域盖板力基本平衡。展开更多
基金Project(2007CB714006) supported by the National Basic Research Program of China
文摘In order to exactly provide scientific basis for pressure dynamic balance control of working chamber of earth pressure balance shield (EPBS),study on optimal arrangement of pressure measurement points in working chamber was conducted. Based on mathematical description of optimal arrangement for pressure measurement points,fuzzy clustering analysis and discriminant analysis were used to divide pressure regions of nodes on bulkhead. Finally,the selection method of optimal measurement points was proposed,and by selecting d6.28 m EPBS as study object,the case study was conducted. By contrast,based on optimal arrangement scheme of pressure measurement points,through adopting weighted algorithm,the absolute error mean of equivalent pressure of working chamber is the smallest. In addition,pressure curve of optimal arrangement points presents parabola,and it can show the state of pressure distribution on bulkhead truly. It is concluded that the optimal arrangement method of pressure measurement points in working chamber is effective and feasible,and the method can provide basis for realizing high precision pressure control of EPBS.
基金Project(2013CB035402) supported by the National Basic Research Program of ChinaProjects(51105048,51209028) supported by the National Natural Science Foundation of China
文摘In order to deal with modeling problem of a pressure balance system with time-delay, nonlinear, time-varying and uncertain characteristics, an intelligent modeling procedure is proposed, which is based on artificial neural network(ANN) and input-output data of the system during shield tunneling and can overcome the precision problem in mechanistic modeling(MM) approach. The computational results show that the training algorithm with Gauss-Newton optimization has fast convergent speed. The experimental investigation indicates that, compared with mechanistic modeling approach, intelligent modeling procedure can obviously increase the precision in both soil pressure fitting and forecasting period. The effectiveness and accuracy of proposed intelligent modeling procedure are verified in laboratory tests.
文摘在离心泵性能数值模拟结果与试验测试结果基本吻合的基础上，对泵平衡孔直径在0-12mm 的范围内，进行泵扬程、效率和轴功率预测，研究泵设计工况下，不同平衡孔直径时，平衡腔内液体压力沿轴向、径向和切向分布规律，以及其对盖板力的影响，并绘制出pfk关系曲线。结果表明：同一流量工况时，平衡孔直径增大到一定值后，轴功率明显增大，效率显著降低，但在大于设计流量工况时，扬程与平衡孔直径无关；同一平衡孔直径下，平衡腔压力沿轴向和切向基本保持不变，压力由泵轴至密封环沿径向增大；在平衡腔内小于平衡孔圆心与泵轴中心垂直距离的半径区域，平衡孔直径越小，压力沿径向越趋近于零，而在平衡腔内大于上述半径区域，平衡孔直径越大，压力沿切向越大；比面积 k ≥2.645时，平衡腔区域盖板力基本平衡。
