This paper presents a new type of subgrade stabilization technique, the lattice-frame-reinforced sheet, which consists of a textile sheet and mortar-injected fabric hoses. The special hoses, which are called “Jackets”, are installed on the textile sheet with lattice-pattern before mortar injection. This sheet can not only distribute surcharge loads but also work as ground beams and furthermore confine the ballasting material on the sheet horizontally.

In order to investigate the performance of this sheet, a real-scale field test was carried out on the soft ground comprising clayey sand, which could not meet the requirements for subgrade of Japanese standard for railway structures. The developed sheet was laid on the soft ground and then a base-course layer was constructed upon the sheet. As a result of plate loading tests, it showed that the coefficient of vertical subgrade reaction of base course was large enough to satisfy the standard value of the requirements.

Consequently, this sheet was applied to actual temporary road works. By conducting plate loading tests, the effect on increasing the coefficient of subgrade reaction was verified, and compared with ‘conventional case’, in which only a sheet was laid on the ground and any frames are not placed on it. These test results showed that the developed sheet was able to substantially increase the coefficient of subgrade reaction and therefore effective to improve the quality of base course.