Deep Excavation Engineering Decompression Precipitation Automatic Control System

With the increasingly complex requirements of underground construction, there are more and more requirements in environmental protection. Since confined aquifer has a huge impact on the pit itself and the surrounding environment, the results of dewatering engineering directly depends on confined water control project. Foundation pit units often take advantage of ultra-drop method under artificial management, which may lead to a big security risk. Based on the analysis of the current domestic and international management information systems, numerical simulation, automatic control system, this paper use Visual Basic as the front-end development language to develop visual application program, use Microsoft SQL Sever2000 to build system database, use ADO objects for database management, use three subsystems (automatic water level monitoring technology, auto-switching power supply technology and remote automatic transmission technology) for field test study. The main findings of this paper are listed as follows:1. Management system was applied to the field of automatic control in confined water dewatering in deep pit project by computer program, which expands the application fields of management information system , and achieves the transformation from to deep excavation decompression precipitation control manual control to automatic control, therefore the risk in decompression dewatering was reduced.2. Data received from automated monitoring system was transformed into graphics by computer program to achieve visualization, therefore data could be tracnsmited in time, errors and human resources costs caused by manual monitoring could be reduced (50% of construction workers in the field could be saved when running the project by initial accounting).3. Remote decision-making can be realized by the adopting of automatic control technology, when confined water pressure exceeded the warning level in deep pit or equipment fail to work, which could greatly reduce the response time from 15 minutes in manual control to 60 seconds. Therefore economic losses caused by accidents in construction could be reduced or avoided. 4. The automatic control technology could limit the confined water level within a certain range to realize dewatering on-demand. So that the impact on the environment caused by over dewatering, such as land subsidence and other geological disasters, could be reduced.Automatic-control system in deep pit confined water dewatering project is a man-machine system that aims to realize information sharing and decision support, and provides services of information collection, procession and transmission, which was built on the idea of management information system, and use computer as the basic information processing, hydro-geological theory as information processing basis and modern communication equipments as information transmitting tools. The system has showed a good performance in Ning-Bo Urban Rail Transit Line East entrance points, in which automatic control in confined water dewatering was achieved, cumbersome steps in manual control was reduced, processes of pit construction controlling was simplified, and automatic data monitoring and transmitting was realized, so that the real-time and accuracy of data in foundation pit construction was improved. The safety of pit construction could be ensured effectively by judgments and warnings made base on the real-time data.