Development of Expert Systems Supported Construction Planning for Shield Tunneling Method

Our expert system aims at the optimum and fast plan making for shield-tunneling works. It is an expert system of applied design problems that integrates such advanced technologies as relational databases, AI, and computer-aided design (CAD). This expert system is able to design and draw a suitable shield machine with an automatic output of design calculations and also specify an optimum control range for the operation of shield-tunneling works. It is possible for a user to quickly make the construction plan for the shield-tunneling works, taking full advantage of the expertise stored in the expert system.The shield-tunneling method is a tunneling method in which soft ground is excavated by a shield machine with a segment lining. In recent years, this method has been widely used in areas where the ground is soft, or the site is in a densely populated area.For shield work, a shield machine and construction plan must be considered for various ground conditions, such as soft ground, gravel, sand layers, and so on, as well as other conditions such as high water pressure or curved alignment. In addition, the growing regulatory concern about environmental protection from ground settlement, vibration, and so on, has made it more difficult to adopt the shield-tunneling method.Conventionally, a construction plan was jointly drawn by experts from the specialized fields, but this approach consumes a large amount of time and labor. Our expert system makes optimum specifications for the shield machine. When we only input construction conditions-- such as the tunnel diameter, design alignment, and contract period as well as the condition of the ground soil, the status of the underground water, and so on--the system automatically leads to the drafting of an optimal shield machine based on its knowledge base. The system also analyzes ground settlement using the finite-element method and selects an optimal code of construction and supplementary construction methods. It then outputs design specifications and design calculations accordingly.