A general analytical model is proposed for predicting three-dimensional seepage into ditch drains through a soil column comprising of three distinct vertical anisotropic soil layers and underlain by an impervious barrier, the drains being fed by a distributed ponding head introduced at the surface of the soil column. The problem is solved for three different situations resulting from three different locations of the water table in the ditches, namely, when the water level lies in the first layer, when it lies in the second layer and finally when it falls in the third layer. The derived solutions are validated by comparing with analytical solutions of others for a few drainage scenarios; in addition, a few numerical checks on them have also been carried out by making use of the Processing MODFLOW environment. From the study, it is seen that ponded drainage of a multi-layered soil is mostly three-dimensional in nature, particularly in locations close to the drains and that the directional conductivities of the layers play a pivotal role in deciding the hydraulics of flow associated with such a system. Further, it has also come out of the study that by suitably altering the ponding distribution at the surface of the soil, the uniformity of water movement in a multi-layered drainage system can be considerably improved mainly if the directional conductivities of the bottom layers are relatively lower than those of the top layer. As soils in nature are mostly stratified and as no analytical solution to the three-dimensional ponded ditch drainage problem currently exists for a layered soil, the proposed solutions are expected to be important additions to the already existing repertoire of drainage solutions on the subject, particularly when looked in the context of reclamation of water-logged and saline soils in layered field situations.

提出了一种通用分析模型，用于预测通过三层垂直各向异性土层的土壤柱渗入排水沟的三维渗流，并通过不透水屏障在排水沟下排水，排水沟由分布在土壤表面的分布池头提供柱。对于由于沟渠中地下水位的三个不同位置而导致的三种不同情况，即当水位位于第一层，第二层以及最后第三层时，该问题得以解决。通过与其他一些排水方案的分析解决方案进行比较，可以验证得出的解决方案；此外，还通过使用Processing MODFLOW环境对它们进行了一些数值检查。从研究中 可以看出，多层土壤的池塘排水本质上大多是三维的，尤其是在靠近排水沟的位置，而且层的方向电导率在决定与这种系统相关的水力方面起着关键作用。 。此外，还通过研究适当地改变了土壤表层的沉积分布，主要是在底层的方向电导率较大的情况下，可以大大改善多层排水系统中水运动的均匀性。相对低于顶层。由于自然界中的土壤大多是分层的，并且由于目前对于层状土壤不存在三维立体沟渠排水问题的解析解决方案，