Abstract
A sand tube has long been applied as riverain, coastal and (fishery) port structures.Its typical damage is the lateral displacement of the part locally rotated by externalforces and scouring. We propose a sand tube with twins. Theoretical and experimental (scale model and prototype) analyses reveal the following results.(1) Eachtube has a cross-section of hydrostatic arch.(2) Typical failure or creep disappears.(3) 2/3-dimensional strengths rise to 1.4 to 2.8 times.(4) Wave force and its momentdecrease to 60% and 25%, respectively.(5) Wave refraction turns erosion into accretion.(6) Breaker impulse is absorved by plastic wave.
