Deformational characteristics of weak sandstone and impact to tunnel deformation

Fu Shu Jeng*, Meng-Chia Weng, Tsan Hwei Huang, Ming Lang Lin

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

48 Scopus citations


In northern Taiwan, a tunnel under construction along a segment where weak sandstone, the Mushan sandstone, was encountered and an excess crown settlement (14-30 cm) has been reported. This paper studies the deformational characteristics of Mushan sandstone and its impact on tunnel deformation. To distinguish the volumetric and the shear deformation of the sandstone, experiments with controlled stress paths, including hydrostatic compression, pure shearing and conventional triaxial compression, were conducted. The measured deformations were then decomposed into elastic and plastic components further exploring the stress-strain behavior of weak sandstone. The results indicate that, similar to other soil-like geo-materials, this sandstone has plastic strain before the stress path reaches the failure envelope and significant shear dilation is induced, especially when approaching the failure envelope. Meanwhile, the distinct features of deformation have also been highlighted by comparing the experimental results to the prediction, derived from existing constitutive models that were originally developed for other geomaterials. These features include significant plastic volumetric strain at low levels of confining stress, suppression of plastic volumetric strain at higher levels of confining stress, and the fact that the actual amount of shear compression is less than that predicted by the model. Numerical analysis indicates that the weak rock leads to the greatest inward displacement, which results from the shear dilation prior to failure state.

Original languageEnglish
Pages (from-to)263-274
Number of pages12
JournalTunnelling and Underground Space Technology
Issue number3
StatePublished - 1 Jul 2002


  • Pure shear stress path test
  • Shear dilation
  • Weak sandstone

Fingerprint Dive into the research topics of 'Deformational characteristics of weak sandstone and impact to tunnel deformation'. Together they form a unique fingerprint.

Cite this