干旱荒漠区公路升级改造既有路面性能检测评价与病害机理研究——以G217线天山神秘大峡谷至库车段为例

Performance Detection, Evaluation and Disease Mechanism Study of Existing Pavement for Highway Upgrade and Reconstruction in Arid Desert Area—A Case Study of G217 from Tianshan Grand Canyon to Kuqa Section

摘要: 为科学评价南疆干旱荒漠区既有公路路面技术状况，合理制定升级改造方案，以G217线天山神秘大峡谷至库车公路升级改造项目为依托，采用路面损坏自动化检测、钻芯取样、探坑开挖、落锤式弯沉仪(FWD)、动力锥贯入仪(DCP)及落球式回弹模量测试仪等多种检测手段，对K1021 + 600~K1080 + 146段58.54 km既有路面进行了系统的技术状况检测与评价。基于检测结果，结合南疆干旱区大温差、盐渍土分布广泛等环境特征，深入分析了既有路面病害类型、分布规律及其成因机理。结果表明：全线PCI平均值为85.2，评定为“良”；RQI平均值为93.4，评定为“优”；RDI平均值为96.42，评定为“优”；SCI平均值为83.4，评定为“良”。路面主要病害为横向裂缝，且裂缝多贯穿沥青面层和水泥稳定砂砾基层，呈现典型的半刚性基层反射裂缝特征；部分路段存在龟裂、块状裂缝及局部沉陷。路床CBR平均值为75.47%，路基回弹模量平均值为268.85 MPa。探坑检测发现局部路段路床填料存在硫酸盐弱盐渍土，盐胀作用对基层结构稳定性构成潜在威胁。基于ABAQUS有限元模型的温度应力与干缩/温缩应力分析表明，水稳基层底部在干缩和温缩耦合作用下的最大拉应力达1.10 MPa，超过材料的典型抗拉强度，从力学角度验证了裂缝的成因。盐渍土路段呈现“低回弹模量–高裂缝密度–低PCI”的耦合特征，盐胀作用通过削弱路基承载力和诱发基层开裂对路面性能产生显著负面影响。基于多指标综合评价结果，提出了针对性的路面升级改造技术对策，包括裂缝处治、基层修复、结构补强及材料优化等措施，为南疆干旱荒漠区类似公路升级改造工程提供了技术参考。

Abstract: To scientifically evaluate the technical condition of existing highway pavement in the arid desert area of southern Xinjiang and reasonably formulate upgrade and reconstruction plans, this study takes the G217 Tianshan Grand Canyon to Kuqa highway upgrade project as the basis. Multiple detection methods including automatic pavement distress detection, core drilling, test pit excavation, Falling Weight Deflectometer (FWD), Dynamic Cone Penetrometer (DCP), and Ball-type Resilient Modulus Tester were employed to conduct systematic technical condition detection and evaluation for the 58.54 km existing pavement from K1021 + 600 to K1080 + 146. Based on the detection results, combined with environmental characteristics such as large temperature differences and widespread saline soil distribution in the arid region of southern Xinjiang, the types, distribution patterns and formation mechanisms of existing pavement diseases were thoroughly analyzed. The results show that: the average PCI is 85.2 (rated “Good”); the average RQI is 93.4 (rated “Excellent”); the average RDI is 96.42 (rated “Excellent”); and the average SCI is 83.4 (rated “Good”). The main pavement distress is transverse cracks, which mostly penetrate through the asphalt surface layer and cement-stabilized gravel base layer, showing typical reflection crack characteristics of semi-rigid base. Some sections have alligator cracking, block cracking and local depression. The average CBR of roadbed is 75.47%, and the average resilient modulus is 268.85 MPa. Test pit detection revealed weak sulfate saline soil in the roadbed fill of some local sections, and salt expansion poses a potential threat to the stability of the base structure. Finite element analysis based on ABAQUS showed that the maximum tensile stress at the bottom of cement-stabilized base under combined drying and thermal shrinkage reached 1.10 MPa, exceeding the typical tensile strength of the material and validating the crack mechanism from a mechanical perspective. Saline soil sections exhibited a coupling characteristic of “low resilient modulus—high crack density—low PCI,” with salt expansion significantly affecting pavement performance through subgrade bearing capacity reduction and base layer cracking. Based on multi-index comprehensive evaluation results, targeted technical countermeasures for pavement upgrade and reconstruction were proposed, including crack treatment, base repair, structural reinforcement and material optimization, providing technical reference for similar highway upgrade projects in the arid desert area of southern Xinjiang.