地下室上浮造成的桩基失效模式有限元分析

Finite Element Analysis of Pile Foundation Failure Modes Caused by Uplifting of Basement

某工程地下室顶板以上覆土重量不足、连续降雨且排水井封填无法及时排水导致地下室发生上浮。现场调查发现,上浮使地下室侧墙、顶板等结构产生裂缝,通过设置排水井、地下室底板开孔泄压后,大幅缓解了地下室上浮,但已造成的损伤是不可逆的,尤其是桩基工程是否被破坏无从得知。为探究地下室上浮是否使桩基失效、以何种模式失效,采用ABUQUS对地下室上浮进行有限元模拟。分析得出,地下室上浮后,管桩与填芯之间的粘结作用被破坏,管桩与填芯脱离,随后,管桩在重力作用下略有下沉,填芯随承台与底板在浮力作用下位移继续增大。因此,地下室上浮问题应引起重视,切忌忽视地下室上浮对隐蔽工程造成的破坏。

Insufficient weight of the overburden soil above the basement roof,continuous rainfall and the blockage of the drainage well usually lead to the uplifting movement of the basement.The field investigation indicated that the uplifting caused cracks at the sidewall,roof and other locations of the basement.By installing drainage wells and basement floor pressure release holes,the basement uplift movement was greatly alleviated.However,the damage caused is irreversible,especially the integrity of the pile foundation is unknown.To explore the basement uplift movement induced pile foundation integrity and failure modes,the commercial finite element analysis software ABUQUS is used to conduct the numerical simulation of the basement movement.The results show that,after the basement movement,the bonding between the pipe pile and the backfill core is damaged.Subsequently,the pipe pile settles slightly under the gravity,and the displacement of the core increases with the pile cap and the bottom plate under the buoyancy.Therefore,the problem of basement uplift movement should be paid attention to,and the damage caused by the basement uplift movement to underground projects should not be ignored.