【摘要】 随着城市现代化建设的发展,对地下工程的需求越来越迫切,地下岩溶的存在是造成城市地面塌陷、影响地下工程建设的主要因素之一.岩溶分布及其引起的塌陷受多种因素影响,尤其是在被第四系沉积物覆盖的情况下,岩溶分布的预测十分困难.通过分析岩溶与岩溶塌陷的主要影响因素,介绍了应用人工神经网络方法进行预测的计算步骤。以唐山市为例,建立了预测模型,预测了唐山市地下岩溶分布,并对城市建设提出了几点建议.更多还原

【Abstract】 With the progress of city modernization,there is an urgent demand for underground engineering.The existence of underground karst is one of the main reasons of collapse,and seriously affects underground engineering construction.Underground karst distribution and collapses are controlled by many factors,so they are very difficulty to be predicted,especially when the karst is covered by the sediments of Quaternary system.The distribution of underground karst and karst collapses are affected by groundwater,strata thickness of Quaternary system,dynamic head of groundwater,beside carbonate strata.By analyzing the main influence factors on karst distribution and collapses,the calculating steps of neural network method is introduced.As an example of Tangshan city,prediction model is constructed.Tangshan is one of the important industrial estates of Hebei province in China,with extensive distribution of carbonate strata and underground karst,so the disaster of karst collapse is very serious.The distribution of underground karst in urban is mainly controlled by thickness of Quaternary system,altitude and depth of groundwater,so those factors are considered in prediction model.In the model,the component number of input layer is 3,and the component number of output layer is 1,plus coefficient of learning is 1.2,inertial coefficient is 0.5.There are two connotative layers.The component number of connotative layer 1 is 4,and the component number of connotative layer 2 is 2.The calculating error is 9%.By iterative calculation of 65 993 times,the distribution of karst in Tangshan city is predicted and some suggestions for city construction are given.更多还原