Experimental Research On Soft Clay Foundation Of Artificial Dredger Filling By Vibration Drainage Consolidation Method

With the increasing scarcity of land resources,the cofferdam and dredger fill reclamation land project has also been increasing.Faced with a large number of soft soil foundations in the reclamation site,the traditional static drainage consolidation method and dynamic drainage consolidation method have certain limitations and deficiencies.Aiming at the inhomogeneity of the reclaimed landfill site and the difficulties in handling soft soil foundations,the experimental design was conducted to investigate the self-weight consolidation law of the dredger fill and the main influencing factors of the dredger fill soft soil foundation by the vibration supercharging and drainage consolidation method.The main conclusions are as follows:(1)In the test of self-weight consolidation of dredger fill,the primary factor influencing the settlement of cohesive soil mixed sand dredger fill is the initial water content;The function of the sedimentation ratio and time of the dredger fill is obtained by fitting the test data.According to the function,the consolidation settling time can be determined according to the percentage of the settling consolidation.When the water content is the same,the consolidation stable settlement and sand ratio are basically linear;From the sedimentation ratio-time logarithm curve,it can be known that the self-weight consolidation process of the dredger fills in three stages,namely the straight section,the upward curve section and the concave curve section.(2)In the one-dimensional vibration consolidation test,the dredger fill soft soil that the water content above liquid limit was vibration consolidation,the main factors affecting the consolidation effect are the upper vertical load,the vibration frequency,the vibration load,and the sand ratio of the soil sample;The upper vertical load and vibration load are positively related to the consolidation effect;The vibration frequency has an optimal frequency for the consolidation effect of the soil sample,and the vibration frequency consolidation effect of each group in the test model is compared,and 15 Hz is obtained as the optimal frequency;The sand ratio is positively correlated with the amount of consolidation settlement.In the process of vibration loading,the soft soil mixing sand is easier to form the drainage channel in the soil,and the pore water pressure change is related to the sand ratio;In the depth direction,the main vibration reinforcement area is within the vertical height range of the vibrator.(3)In the multi-vibrator model box test,the horizontal direction acceleration of the coupled vibration of the double vibrator is 2.5~3 times the peak value of the single vibration wave,and the acceleration of the coupling vibration of the fourth vibrator is 3.5~4.5 times the peak value of the single vibration wave;The settlement curve of the model box corresponds to the vibration loading energy.Compared with the loading stage of the double vibrators and four vibrators,the displacement curve shows a significant slope change,and the settlement rate increases;The variation curve of the drainage rate with the loading process shows that the convex angle is the time interval during which the vibration boosting process is performed,and the drainage rate in the vibration range is 1.2~2.6 times that in the non-vibration range;After the consolidation is completed,the vibration consolidation effect at 0.75 D from the center of vibration is obvious.The processing radius is 1.5D.