One embodiment of the present invention provides for a subterranean structure, having a continuous ribbon slab having a plurality of flights fabricated from concrete. The ribbon slab defines periodic openings therein which generally align between adjacent flights. Another embodiment provides for a method of fabricating a subterranean structure. The method includes excavating soil to form a downward sloping ramp, and forming a concrete slab on the downward sloping ramp. The method further includes continuing to excavate soil to extend the downward sloping ramp to a location under the concrete slab, and continuing to form the concrete slab on the downward sloping ramp so that a subterranean structure is formed having an essentially continuous concrete slab with a first portion which is above and spaced-apart from a second portion.
CROSS REFERENCE TO RELATED APPLICATIONS
This application claims priority to U.S. Provisional Patent Application serial No. 60/385,325, filed Jun. 3, 2002, and entitled "Methods and Apparatus for Constructing Subterranean Structures".
Disclosed herein is a support system that is temporarily placed below ground for preventing collapse of the excavated ground when a subway is constructed or a basement of a building is built. The excavated ground or load is supported by means of supporting members, the supporting members being pre-stressed by means of tensioning members and tendon support members serving to support the tensioning members. Consequently, the number of struts for supporting vertical piles and wales is considerably reduced so that obstacles in the under-ground space when it is excavated are removed. Furthermore, the constructional efficiency of the underground space is greatly improved, and the cost of construction is sharply reduced.
