Study Of Creep Settlement And Control Measures Of Oil Tank Group On The Soft Foundation

In the design of storage tank foundation at present,tank settlement calculation generally refers to the primary consolidation settlement,and rarely considers the creep settlement quantificationally.In order to provide references for the reinforcement of the large sized tank on soft soil foundation,this paper has studied the soft soil creep effects on tank settlement and uneven settlement,and the measures to control the creep of tank soft soil foundation.Taking thick soft soil foundation as an example,this paper has studied the consolidation settlement in the water filling stage and the creep settlement after putting into use of the oil tank group.The effects of several common soil foundation treatment methods are simulated.Some conclusions are as follows:1.Considering the creep of soft soil foundation,tank settlement and uneven settlement in the process of normal use are much larger than that with no creep.The soft soil creep has a great influence on tank settlement and uneven settlement and it must be considered into the tank design.2.In the stage of water filling and leak detection,if tanks in the tank group fill water synchronously,the settlement and uneven settlement of each tank are the same after the completion of the water filling,and each tank inclines towards the direction to close to each other.If tanks fill water in order,the settlement and uneven settlement of the first tank are larger,and gradually reduced slightly according to the order.All the tanks also incline towards the direction to close to each other.3.In normal use,due to the creep of soft soil foundation,tank settlement growth rate is large relatively in the early stage,and then reduces and remains the same.In the early days,tank uneven settlement increases slowly and then begins to increase.Water filling order and tank group effect have little influence on tank creep settlement in normal use.4.Treating the soft soil foundation of storage tanks using pre-loading method can effectively reduce the tank settlement and uneven settlement in normal use,but the reduction degree is not very big.Extending the pre-loading time can improve the reduction degree of tank settlement and uneven settlement,but the effect is not obvious.5.Treating the soft soil foundation of storage tanks using dynamic replacement method can reduce storage tank settlement and uneven settlement,but have little effect on controlling the creep settlement of the soft substratum.Increasing the replacement thickness and improving the elasticity modulus of the reinforcement layer can only reduce tank settlement and uneven settlement slightly.6.Comparing to the natural soft soil foundation and the foundation treated by pre-loading method and dynamic replacement method,CFG pile composite foundation can effectively control the creep settlement of tank foundation,and reduce tank settlement in large degree.To treat the thick soft soil foundation of storage tank,CFG pile composite foundation method should be firstly chosen.Increasing pile length or pile diameter,or reducing pile spacing can reduce tank settlement,but the reduce degree is small.A variety of comprehensive factors in a project,such as economic costs,construction difficulties and time limit,should be considered to determine reasonable parameters of CFG piles.