Longyou grottoes have characteristics of shallow embedding

large span and lying in soft rock. The one of important reason for that the grottoes have kept stability for thousands years is that some special structural shapes are adopted

except the integrality of rock mass is better and the holding action of the full water in caves. In Longyou Grottoes

fishtail pillar structures

used to increase the longitudinal length of support area and enlarge chapiter structures (named as pillar caps)

gradient roof structures in longitudinal direction and arch-type structures in transverse direction are utilized separately. By comparing these structural shapes with modern structural mechanics theory

results revealed that they correspond well. It is embodiment of the ancients? structural mechanics idea

and also revealing the ancients? wisdom and creativity. By digging and studying structural mechanics idea of containing in grottoes

it may be used to steer more and more underground engineering construction of today

and making the past serving the present.