Zeng Yang, Xie Yongli, Liu Jiaxiang
School of Highway, Chang'an University, Xi'an 710064, China.
Polymers (Basel). 2025 Jul 2;17(13):1856. doi: 10.3390/polym17131856.
Grouting is an effective method for enhancing the stability of poor strata such as sand layers. The performance of the grouting materials directly influences the effect of stratum reinforcement. To meet the urgent demand for efficient grouting materials, this study selected a high-permeability, flexible polymer (PFP) as the grouting material. The influences of the PFP content, curing time, and dry density on the mechanical and impermeable properties of PFP-improved sand were systematically analyzed via unconfined compressive tests, split tensile tests, and variable head permeability tests. Moreover, the section morphology and pore characteristics of the PFP-improved sand were qualitatively described and quantitatively analyzed by scanning electron microscopy (SEM) and image processing software. The results indicated that the mechanical properties and impermeability of the test sand were significantly improved by adding the PFP, and the improvement effect continued to increase with increasing PFP content, curing time, and dry density. The compressive strength and splitting tensile strength of PFP30 (PFP content of 30%, curing time of 28 d, dry density of 1.5 g/cm) reached 8.3 MPa and 1.4 MPa, respectively. The permeability coefficient reduced to 5.41 × 10 cm/s. The microscopic results revealed that the PFP effectively cemented the isolated sand particles through bridging, filling, and encapsulation as well as substantially filled the internal pores of the test sand. The percentage of the pore area, the total number of pores, and the maximum pore diameter of the test sand were significantly reduced. The pore area percentage, the total number of pores, and the maximum pore diameter of PFP30 were reduced to 0.124, 30, and 213.84 μm, respectively. This study reveals that PFP has potential for application in the grouting construction of poor strata, such as sand layers.
注浆是提高砂层等软弱地层稳定性的有效方法。注浆材料的性能直接影响地层加固效果。为满足对高效注浆材料的迫切需求，本研究选用了一种高渗透性、柔性聚合物（PFP）作为注浆材料。通过无侧限抗压试验、劈裂拉伸试验和变水头渗透试验，系统分析了PFP含量、养护时间和干密度对PFP改良砂力学性能和抗渗性能的影响。此外，通过扫描电子显微镜（SEM）和图像处理软件对PFP改良砂的截面形态和孔隙特征进行了定性描述和定量分析。结果表明，添加PFP可显著提高试验砂的力学性能和抗渗性，且随着PFP含量、养护时间和干密度的增加，改良效果持续增强。PFP30（PFP含量30%、养护时间28 d、干密度1.5 g/cm）的抗压强度和劈裂抗拉强度分别达到8.3 MPa和1.4 MPa。渗透系数降至5.41×10 cm/s。微观结果显示，PFP通过桥接、填充和包裹有效地胶结了孤立的砂粒，并大量填充了试验砂的内部孔隙。试验砂的孔隙面积百分比、孔隙总数和最大孔隙直径均显著降低。PFP30的孔隙面积百分比、孔隙总数和最大孔隙直径分别降至0.124、30和213.84μm。本研究表明，PFP在砂层等软弱地层的注浆施工中具有应用潜力。
