New techniques and methods for 3D geo-mechanical model test are presented in this paper. The new model material NIOS with high density and low cost; the so-called DPSS (Discrete Principal Stress Surface) loading concept, the loading and monitoring system for the generation of the 3D initial stress field of the model test, also the special techniques and apparatuses for modelling the excavation of caverns located deep inside the model material, are developed and introduced. By adopting those new techniques, a very large 3D geo-mechanical model test with high comparability for a newly designed underground powerhouse has been successfully fulfilled.
Neue Techniken und Methoden fuer 3D geomechanischen Modellversuch wurden in diesem Artikel vorgestellt. Ein neues Modellmaterial mit hocher Dichte und niedrigem Preis, ein sogenanntes DPSS (Discrete principal stress surface) Ladenkonzept, ein Laden- und Überwachungssystem fuer die Erzeugung des 3D primaren Spannungsfelds und ueberdies spezielle Techniken und Maschinen fuer das Ausbruch der tief in dem Versuchsmodell liegenden Kaverne wurden entwickelt. Bei Anwendungen dieser neuen entwickelten Techniken wurde ein sehr groβer 3D Modellversuch mit groβem Maβstab fuer ein geplantes unterirdisches Kraftwerkerfolgreich durchgefuehrt.
le test de modèl de Nouvelles techniques et methodes pour la geo-mecanique 3D est figure dans ce papier. Le nouveau modèle de materiels NIOS avec la haute densite et le coût bas; la conception proposee de chargement DPSS (Discrete Principal Stress Surface), le système de chargement et de moniteur pour la generation de champs de stress initial du test de modèle, ainsi que les techniques et appareils speciaux pour modeler les excavations de caverns profondement localisees dans l'interieur du materiel de modèle, sont developpes et introduits. A travers l'adoptation de ces nouveaux techniques, le test de modèle de la geo-mecanique très large 3D avec la haute comparabilite pour actualiser une nouvelle etude de la centrale electrique sous-terraine a dejà accompli avec succès.
The method of geo-mechanical modeling was dominated in the period of 70's to 80's last centruy for the research works of rock foundations and underground engineering (Heuer, R.E., Hendron, A.J. et al.). However, it has been decreased obviously since the numerical analysis methods developed rapidely with the powerful computers. But still some of the research works should be mentioned: Corbin. G.E. (1975) performed physical model tests to the development of a rational design approachs in the use of spilling reinforcement in underground construction. Nagai T. (1996) studied the mechanical behaviour of rock masses around an underground opening using physical model tests. Zhao ZY (1988) studied the surrounding rock stability of the underground openings using model test and gained the distributions of the stress and displacement on the rock around the openings. Chen X. (1994) studied the surrounding rock stability of underground openings using three dimensional geo-mechanical model test, with a size of the model of 1.16×1.16×1.20m. It shows that for complecated projects and geological conditions, physical geo-mechanical modelling may be necessary. However, because of great difficaulties existing, those model research works were mostly 2D, or 3D in small scale, could not simulate the underground caverns in its real meaning.
