水位升降和潮汐水位作用下围堰的安全稳定性OACSTPCD

In order to analyze the safety and stability of coastal area cofferdam under the effects of the rising and falling of water level and tide level,basing on the engineering example of Jimei Island Station of Xiamen City,applying the seepage theory of unsaturated soil of Plaxis finite element program,and using the finite ele-ment strength reduction method,the safety and stability of cofferdam under the effects of different rising and falling speed of water level and tidal level circulation is carried out,the mechanism of the influence of water level change on the stability of cofferdam is analyzed through the change curve of safety factor of cofferdam.The results show that the safety factor of cofferdam decreases when the water level rises,and the faster the water level rises,the greater the reduction rate of the safety factor of cofferdam.There is a critical water level drop rate when the water level drops,the critical water level drop rate is 1.0 m·d-1,when the water level drop rate exceeds the critical water level drop rate,the safety factor of cofferdam first decreases and then in-creases,when the water level drop rate is less than the critical water level drop rate,the safety factor of coff-erdam increases gradually.The safety factor of cofferdam increases at low tide and decreases at high tide,the greater the tidal amplitude,the greater the increment of safety coefficient of cofferdam increases,the increment of safety factor of cofferdam between two adjacent cycles gradually decreases and tends to be stable with the in-crease of cycle times.