The Supperconducting Super Collider (SSC) being built in Texas, U.S.A. requires two huge underground chambers, each measuring approximately 105 m long, 35 m wide and 60 m high, to house the heavy detector equipment weighing over tens of thousands of metric tonnes. The chambers also called as experimental halls are to be excavated in rock formation consisting of weak marl and competent chalk. This paper focuses on how numerical modeling helps guide the design of the hall excavation sequence and rock reinforcement systems. It has been indicated that control of the marl/chalk contact region is crucial and that the construction sequence plays a very important part in selecting the rock support systems and dimensioning the rock anchors.


Le Superconducting Super Collider (SSC) en construction au Texas, Etats-Unis demande deux immenses chambres souterraines, chacun mesurant 105m de long, 35 m de large et 60 m de haut approximite. Le but des souterrains est de tenir les detecteurs des particules sub atomique qui pesent plus de 10,000 t. Les souterrains sont aussi appelle Chambres Experimentales qui sont extractes dans le faible rocher et la craie. Cet article explique comment l'analyze numerique sur l'ordinateur assiste le systeme et l'ordre d'extraction et la construction du systeme pour reenforcer les rochers. Le model et tres important pour choisir le system le plus economique et pour choisir les dimensions de ce systeme.


Der Superconducting Super Collider (SSC), der gegenwartig in Texas, U.S.A., gebaut wird, erfordert zwei grosse, untertagige Testkammern; jede Kammer ca 105 m lang, 35 m breit und 60 m hoch, zur Aufnahme schwerer Detektor Ausruestungen, die mehrere Zehntausend Tonnen wiegen. Die Kammern, auch Experimentier-Hallen genannt, muessen in einem Gebirge ausgehoben werden, das aus weichem Mergel und festerem Kreidekalkstein besteht. Diese Aufsatz befaβt sich mit der Frage, in welcher weise numerische Modelle bei der Planung der Abfolge in Ausbruch und Felssicherung behilflich sein koennen. Es gibt Anzeichen, daβ die Kontrolle ueber der Kontaktzone zwischen Mergel und Kreidekalkstein einen Kritischen Punkt bildet und daβ die Einzelnen Baubschnitte eine bedeutsame Rolle spielen in der Wahl der Ausbausysteme und deer Dimensionierung deer Felsanker.


Two large underground chambers, also referred to as experimental halls, will be constructed in Texas, U.S.A. to house two expensive and precision detectors needed for analyses of the products of the collision between two proton particle beams colliding with each other at the speed approaching speed of light. As is shown in Figure 1, the locations identified by IR 1, IR 4, IR 5 and IR 8 are the target places to excavate the two chambers along the giant underground tunnel of over 85 km in length. Since the underground structures are expected to satisfactorily serve for several decades of time, the long-term stability of the hall in general and the foundation in particular was considered to be the most important factor in selection of the location of halls. Consequently, extensive numerical analyses have been performed to lend a helpful hand to design. The main objectives of numerical analyses were 1) to cope with the excavation complexities which go beyond the reach of other analysis tools such intuition, analytical approach, 2) to help evaluate different hall excavation methods with an attempt towards an optimum design and 3) to allow for rapid revaluation of the design when design parameters were changes. Since the two detectors are very costly and highly sensitive instruments, weighing 45,000 and 15,000 metric tons respectively, hall excavation and construction must be accomplished in a rather precise manner in order to satisfy the tight construction tolerances specified for each instrument.

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