tetrapods are used to enforce coastal structures such as seawalls and breakwaters in chumphon province, thailand

absorb are armour attenuator beach beachfront breakwaters cement chumphon coast coastal coastline concrete crack enforce engineering erosion heap inshore interlock interlocking landscape made marine natural nature objects old outdoor pile prevention protect protection province safe sea seaside seawalls shape shelter shore shoreline structure structures such tetrahedral tetrapods thailand they use used water waterfront wave