原状磷石膏基固化材料固化粉质土性能评价

针对原状磷石膏耐水性差、体积稳定性差和利用率低等问题，以原状磷石膏为主要原料，富硅铝材料、增强材料和耐水材料作为辅助材料制备固化材料，选择原状磷石膏基固化材料（40%原状磷石膏+30%富硅铝材料+30%增强材料）和掺耐水材料的原状磷石膏基固化材料（40%原状磷石膏+30%富硅铝材料+30%增强材料+外掺5%耐水材料）对粉质土进行固化试验，评价固化土的力学性能、水稳性及长期耐水性、体积稳定性和环境毒性。结果表明：固化材料掺量为12%，其中耐水材料掺量占固化材料的5%时，7 d和28 d的无侧限抗压强度分别为4.1 MPa和4.7 MPa，较未掺耐水材料试样分别提高了37%和12%；掺耐水材料试样标养28 d后浸水60 d，强度可达3 MPa，高于未掺耐水材料的2.7 MPa；体积膨胀率在浸水720 h后达到稳定值0.07%，浸出液检测结果表明没有环境危险。原状磷石膏基固化材料较传统的二灰土力学性能、水稳性及长期耐水性、体积稳定性都得到明显改善。

Performance evaluation of solidified silty soil curing by original phosphogypsum-based solidified materials

In order to solve the problems of poor water resistance, poor volume stability and low utilization rate of original phosphogypsum, curing materials were prepared with original phosphogypsum as the main raw material, silicon-rich aluminum-rich materials, reinforced materials and water-resistant materials as auxiliary materials. Undisturbed phosphogypsum-based solidified materials (40% undisturbed phosphogypsum + 30% silicon-rich aluminum materials + 30% reinforced materials) and undisturbed phosphogypsum-based solidified materials mixed with water-resistant materials (40% undisturbed phosphogypsum + 30% silicon-rich aluminum materials + 30% reinforced materials + 5% water-resistant materials) were selected to solidify silty soil, and the mechanical properties, water stability, long-term water resistance, volume stability and environmental toxicity of the solidified soil were evaluated. The results show that the content of curing material is 12%, and when the content of water-resistant material accounts for 5% of the curing material, the unconfined compressive strength of 7 d and 28 d is 4.1 MPa and 4.7 MPa, respectively, which is 37% and 12% higher than that of the samples without water-resistant materials, and the strength of the samples with water-resistant materials after standard curing for 28 d is 60 d, which is higher than that of 2.7 MPa without water-resistant materials. The volume expansion rate reached a stable value of 0.07% after soaking for 720 h, and the test results of the leaching solution showed that there was no environmental hazard. Compared with traditional lime-fly ash soil, the mechanical properties, water stability, long-term water resistance, volume stability of undisturbed phosphogypsum-based solidified materials are obviously improved.