Enzyme induced carbonate precipitation (EICP) is an innovative ground improvement technique which can enhance soil properties including soil strength, stiffness and hydraulic conductivity by cementing and filling soil pores. The calcium carbonate precipitation has the potential to influence the water retention ability through altering pore-size distribution and void ratio. This study aims to investigate the effects of soybean urease induced carbonate precipitation on the water retention ability of the ISO standard sand. Three tests using simplified evaporation method were performed to measure the water retention curves (WRCs) of one untreated sand and two treated sands with 0.5 and 1 mol/L urea-calcium chloride solutions and soybean urease liquid. Scanning Electron Microscopy (SEM) and Mercury Intrusion Porosimetry (MIP) were used to assist the interpretation. A new and simple WRC model for the EICP-treated sand is proposed with an attempt to consider the effects of calcium carbonate precipitation on the void ratio as well as the pore-size distribution. Based on the measured results, it is found that the calcium carbonate precipitation is prone to fill the macro-pores in the sand, resulting in an increase in air-entry value with the increasing concentration of urea-calcium chloride solutions. The pore-size distribution becomes more uniform with the increase in calcium carbonate precipitation amount, leading to an increase in desorption rate of WRC. The proposed model is found to be able to well simulate the WRC of sand.

酶促碳酸盐沉淀（EICP）是一项创新的地面改良技术，可通过胶合和填充土壤孔隙来增强土壤特性，包括土壤强度，刚度和水力传导率。碳酸钙沉淀有可能通过改变孔径分布和孔隙率来影响保水能力。本研究旨在研究大豆脲酶引起的碳酸盐沉淀对ISO标准砂的保水能力的影响。进行了三个使用简化蒸发法的测试，以测量一种未经处理的沙子和两种经处理的沙子（含0.5和1 mol / L尿素-氯化钙溶液和大豆脲酶液体）的保水曲线（WRC）。扫描电子显微镜（SEM）和水银压入孔隙率法（MIP）用于辅助解释。提出了一种新的简单的WRC模型，用于EICP处理过的砂子，试图考虑碳酸钙沉淀对空隙率以及孔径分布的影响。基于测量结果，发现碳酸钙沉淀易于填充沙子中的大孔，从而随着尿素-氯化钙溶液浓度的增加，进气值增加。随着碳酸钙沉淀量的增加，孔径分布变得更均匀，导致WRC的解吸速率增加。发现所提出的模型能够很好地模拟沙子的WRC。提出了一种新的简单的WRC模型，用于EICP处理过的砂子，试图考虑碳酸钙沉淀对空隙率以及孔径分布的影响。基于测量结果，发现碳酸钙沉淀易于填充沙子中的大孔，从而随着尿素-氯化钙溶液浓度的增加，进气值增加。随着碳酸钙沉淀量的增加，孔径分布变得更均匀，导致WRC的解吸速率增加。发现所提出的模型能够很好地模拟沙子的WRC。提出了一种新的简单的ERC处理过的砂子WRC模型，试图考虑碳酸钙沉淀对空隙率以及孔径分布的影响。基于测量结果，发现碳酸钙沉淀易于填充沙子中的大孔，从而随着尿素-氯化钙溶液浓度的增加，进气值增加。随着碳酸钙沉淀量的增加，孔径分布变得更均匀，导致WRC的解吸速率增加。发现所提出的模型能够很好地模拟沙子的WRC。结果发现，碳酸钙的沉淀易于充满沙子中的大孔，随着尿素-氯化钙溶液浓度的增加，进气值增加。随着碳酸钙沉淀量的增加，孔径分布变得更均匀，导致WRC的解吸速率增加。发现所提出的模型能够很好地模拟沙子的WRC。结果发现，碳酸钙的沉淀易于充满沙子中的大孔，随着尿素-氯化钙溶液浓度的增加，进气值增加。随着碳酸钙沉淀量的增加，孔径分布变得更均匀，导致WRC的解吸速率增加。发现所提出的模型能够很好地模拟沙子的WRC。