| In order to study the consolidation characteristics of soft soil foundation treated by the consolidation method of preloading drainage under heap load.Based on the analysis of consolidation theory of soft soil foundation treated by preloading drainage consolidation method in Shantou,Guangdong province,a large-size consolidation instrument with drainage unit was designed.On this basis,the finite element numerical analysis model is established.The theoretical calculation results,finite element numerical analysis results and field monitoring results were compared and analyzed.Therefore,the following results were obtained.(1)The composite consolidation coefficient is deduced theoretically.The ratio of the composite consolidation coefficient to the vertical consolidation coefficient is inversely proportional to the well diameter ratio factor.And it is proportional to the square of the ratio of the vertical drainage distance to the effective drainage diameter.Furthermore,it is proportional to the ratio of the radial to the vertical consolidation coefficient.Consolidation test was conducted to determine the composite consolidation coefficient of large soil samples containing vertical drainage units(diameter of soil samples is 80 mm,100mm,and 120 mm,respectively).(2)In the laboratory test of soft soil filled with high plasticity in Shantou,the composite consolidation coefficient decreases with the increase of the well diameter ratio,effective drainage diameter and drainage height.Which is about 25% larger than the average theoretical value,and the theoretical value is modified.When the borehole diameter ratio is 20,compared with the conventional consolidation test,the composite consolidation coefficient of the100mm×100mm large-size consolidation test is about 1.4 times that of the vertical consolidation coefficient,and the vertical consolidation coefficient is about 1.35 times that of the conventional consolidation test.(3)Based on the theory of composite consolidation coefficient of consolidation of Shantou reclaimed soft soil drainage consolidation engineering example is calculated.And theresults show that the area of field monitoring the degree of consolidation is 88%,the theory of degree of consolidation around 6% larger than the field monitoring final degree of consolidation.But the first two levels of stack in the process of consolidation of the field monitoring value than the calculated value is faster.The field monitoring value of the final settlement is 1262 mm,and the theoretical value is about 17% larger than the field monitoring value.(4)According to Shantou reclaimed soft soil drainage consolidation project example as the background,the drain line model and the coefficient of the composite model is established for numerical simulation of the model to simulate the calculation results show that the average settlement drain line value larger than the field monitoring value 19%,coefficient of the composite model value larger than the field monitoring value 13%,coefficient of the composite model and field monitoring values closer.The final average consolidation degree of the two models was about 97%,and the field monitoring value is 9% than before.The law of pore water pressure is obvious in numerical simulation,and the drainage line model is closer to the field monitoring value.The maximum lateral displacement at the foot of the slope is the junction of two layers of soft soil. |
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