离心模型试验模拟塑料排水板处理软土地基的方法和应用

采用大型土工离心机对某工程近海软土地基上堤坝施工期及运行期进行了模拟。试验中采用停机加载法模拟分级施工加载过程,原型中采用塑料排水板固结法处理软土地基,模型中则根据固结过程相似的原理,换算成等效圆截面排水体,在模型制作中采用等效透水滤芯进行模拟。根据激光位移传感器和孔隙水压力传感器数据可以得出相应原型软土地基的沉降特性和孔隙水压力变化情况。根据试验得到的沉降曲线,采用"经验双曲线法"推算出了地基最终沉降,然后得出按沉降推算的分层地基平均固结度随时间的变化。对比试验模拟得到的软土地基固结度和理论计算结果,二者基本接近,表明塑料排水板模拟方法用于离心模型试验是可行的。

THE METHOD AND APPLICATION OF CENTRIFUGAL MODELING TO VERTICAL STRIP DRAINS IN SOFT FOUNDATION

Centrifuge model tests were carried out to simulate the construction and operation of the dike on a soft soil foundation by using the geotechnical centrifuge in IWHR. The vertical strip drains in the foundation were simulated by a kind of model cylinder vertical drains, based on the principle of same consolidation degree in the foundation in average for both type of drains. During the model tests, the construction processes were simulated by loading dike materials layer by layer when the centrifuge stops running. Laser displacement sensors and the pore pressure transducers were installed for model measurement of settlement and pore pressure variation during tests. Based on the measured data, the final settlement of the dike was estimated by using experience hyperbolic method. And the consolidation degree of the foundation over time was also calculated, which indicates the average consolidation of the sludge and the sand under the dike. Comparing the consolidation degree of the soft foundation from the results of pore water pressure and that of the theoretical calculation, it shows that the simulation method of vertical strip drains presented in this paper is feasible and acceptable. The comparison of the model test results with that of theoretical calculation indicates that the strip drain simulation method described in this paper is acceptable.