Abstract Biopolymer treatment has been considered as one of the most sustainable methods of soil improvement for controlling subsurface water flow. It is able to alter pore structure and hence water retention behaviour of soils, as demonstrated by extensive experimental results in the literature. To predict the effects of biopolymer treatment on the surface and subsurface water flow, it is important to develop a proper water retention model for biopolymer-amended unsaturated soils. The existing models do not consider the complex biopolymer-soil interactions. In this study, a new soil water retention model is developed with a consideration of various mechanisms of biopolymer-soil interactions, including (1) biopolymer occupies some pore space and therefore changes the pore volume of soil; (2) biopolymer itself is able to hold water; (3) the swelling of biopolymer may induce soil volume change; (4) the swelling of biopolymer is partially constrained by soil particles. To verify the new model, it is applied to simulate the measured water retention curves of seven soils. The measured and calculated results show good agreement. It is convincingly demonstrated that the new model is able to well capture the water retention behaviour of various soils amended by different biopolymers.

中文翻译：

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考虑生物聚合物-土壤相互作用的保水模型

摘要 生物聚合物处理被认为是控制地下水流的最可持续的土壤改良方法之一。正如文献中广泛的实验结果所证明的那样，它能够改变孔隙结构，从而改变土壤的保水行为。为了预测生物聚合物处理对地表和地下水流的影响，重要的是为生物聚合物修正的不饱和土壤开发适当的保水模型。现有模型没有考虑复杂的生物聚合物-土壤相互作用。在这项研究中，考虑到生物聚合物-土壤相互作用的各种机制，开发了一种新的土壤保水模型，包括（1）生物聚合物占据了一些孔隙空间，因此改变了土壤的孔隙体积；(2) 生物聚合物本身是能够持水的；(3)生物聚合物的膨胀可能引起土壤体积变化；(4) 生物聚合物的膨胀部分受到土壤颗粒的限制。为了验证新模型，将其应用于模拟七种土壤的实测保水曲线。测量和计算结果显示出良好的一致性。令人信服地证明，新模型能够很好地捕捉由不同生物聚合物修饰的各种土壤的保水行为。