The subgrade of old railway tracks often exhibits poor geotechnical behaviour, particularly regarding the soils on which the ballast layer rests. Such poor behaviour implies significant maintenance costs and possession times. The reinforcement of subgrade soils by injection of binders may mitigate these malfunctions, but previous applications showed some limitations, and the quality of the results depends on many factors. Herein, the authors present some studies on the development of a subgrade reinforcement method, which minimises the impact on train operation, by using short soil–binder columns, formed with grouts injected into the subgrade by drilling through the ballast layer. Laboratory studies were performed to determine the strength and deformability of the mixtures of a clay soil with lime or cement. To assess the improvement of the geotechnical characteristics of that soil and to determine the permanent deformation of the track structure under cyclic loading, tests were performed on full-scale physical models. A reduction of about 60–80% was observed in settlement amplitudes of the reinforced physical models under cyclic loading. Lastly, the reinforcement method was employed on a track in operation that exhibited a poor behaviour, the subsequent geotechnical improvements were assessed and the dynamic responses of the track before and after grouting were compared. After the treatment, a general reduction of about 15–20% was observed in peak vertical accelerations measured on the sleepers. The results suggest that, from both the technical and the economic viewpoints, the proposed reinforcement method is a valid alternative for rehabilitating railway platforms, notably in old single-track lines.

旧铁路轨道的路基经常表现出不良的岩土性能，特别是压载层所在的土壤。这种不良行为意味着大量的维护成本和拥有时间。通过注入粘结剂来加固路基土壤可以减轻这些故障，但是先前的应用显示出一些局限性，并且结果的质量取决于许多因素。在这里，作者们提出了一些路基加固方法的研究，该方法通过使用短的土工结合柱，通过灌浆通过压实层将水泥浆注入路基中，来最小化对火车运行的影响。进行了实验室研究，以确定粘土土与石灰或水泥的混合物的强度和可变形性。为了评估这种土壤的岩土特性的改善并确定循环荷载下轨道结构的永久变形，对全尺寸物理模型进行了测试。在循环荷载下，增强物理模型的沉降幅度降低了约60–80％。最后，在运行性能较差的轨道上采用了加固方法，对随后的岩土工程进行了评估，并比较了灌浆前后轨道的动力响应。治疗后，在轨枕上测得的垂直加速度峰值总体降低了约15-20％。结果表明，从技术和经济角度来看，