Zhao Weifan, Guo Chengchao, Wang Chaojie, Wang Yuke, Wang Lina
College of Water Conservancy Engineering, Zhengzhou University, Zhengzhou 450001, China.
National Local Joint Engineering Laboratory of Major Infrastructure Testing and Rehabilitation Technology, Zhengzhou 450001, China.
Materials (Basel). 2022 Sep 25;15(19):6647. doi: 10.3390/ma15196647.
The reinforcement and durability of loess are of great importance for road performance. In this study, a self-designed grouting system and newly permeable polymers were adopted to investigate the mechanical properties and durability of solidified loess (SL), considering different dry densities and water contents. The unconfined compression test and piezocone penetration (CPTU) test were used to examine the mechanical properties. The mechanism of the loess solidified by permeable polymer was analyzed from the micro-level by SEM, MIP, and XRD tests. The test results show that the effect of polymer grouting is obvious, the unconfined compressive strength (UCS) of the SL after grouting is as high as 3.05−5.42 MPa; it is 11.83−20.99 times that of unsolidified loess (UL). The UCS of the SL after grouting is inversely proportional to the dry densities and water contents. After 56 days of immersion, the SL still shows a high compressive strength. The additional erosion of the SL was not caused by the salt solution; the durability is significantly better than that of cement mixing soil. The sensitivity of various factors on the UCS of the SL are service environment > water content > dry density. The SEM tests clearly show that the gel formed by the reaction of the polymer with water on the surface of soil particles makes the bond of soil particles tighter. It can be observed from the MIP test that the cumulative mercury of SL was 0.115 mL/g, which was 33.72% of UL (0.341 mL/g), and the cumulative mercury of SL after immersion in water and salt solutions was 0.183 mL/g and 0.175 mL/g, which was 53.7% and 51.3% of UL (0.341 mL/g), respectively. The XRD results show that there are no other new mineral components produced after grouting and the spacing between crystalline planes decreases, which proves that permeable polymer grouting makes the soil denser and does not erode the soil particles.
黄土的加固与耐久性对道路性能至关重要。本研究采用自行设计的注浆系统和新型渗透性聚合物，考虑不同干密度和含水量，研究固化黄土（SL）的力学性能和耐久性。采用无侧限抗压试验和孔压静力触探（CPTU）试验检测力学性能。通过扫描电子显微镜（SEM）、压汞法（MIP）和X射线衍射（XRD）试验从微观层面分析渗透性聚合物固化黄土的机理。试验结果表明，聚合物注浆效果明显，注浆后SL的无侧限抗压强度（UCS）高达3.05−5.42MPa；是未固化黄土（UL）的11.83−20.99倍。注浆后SL的UCS与干密度和含水量成反比。浸泡56天后，SL仍具有较高的抗压强度。盐溶液未对SL造成额外侵蚀；其耐久性明显优于水泥搅拌土。各因素对SL的UCS的敏感性为：服役环境＞含水量＞干密度。SEM试验清楚地表明，聚合物与土壤颗粒表面的水反应形成的凝胶使土壤颗粒的结合更紧密。从MIP试验可以看出，SL的累计汞侵入量为0.115mL/g，是UL（0.341mL/g）的33.72%，浸泡在水和盐溶液中的SL的累计汞侵入量分别为0.183mL/g和0.175mL/g，分别是UL（0.341mL/g）的53.7%和51.3%。XRD结果表明，注浆后没有产生其他新的矿物成分，晶面间距减小，这证明渗透性聚合物注浆使土壤更密实，且不会侵蚀土壤颗粒。
