Abstract Saline rock is extremely unfavorable to tunnel engineering. In this study, based on a tunnel passing through thick chloride saline rock on the China-Laos Railway, its engineering geological characteristics are studied.Firstly, the saline rock engineering section is divided into the low salt content section and the high salt content section based on salt content. Then, the sections with different salt contents are tested using thin section identification,X-ray diffraction, strength test, water quality analysis, corrosion and expansibility tests to quantitatively study their physical, mechanical, hydrochemical, corrosion and expansibility and other engineering geological characteristics.The results indicate that the mineral components of the saline rock in this section is mainly rock salt (NaCl). The compressive strength of saline rock in the high salt content section is significantly lower than that of saline rock in the low salt content section. The main anions and cations in the groundwater come from the dissolution of salt, and as the salt content increases, the environmental action level of the groundwater gradually increases. Saline rock is corrosive, and the maximum upper corrosion rate in the high salt content section is 8.846~10.540 mm/h, with an average of 9.527 mm/h. Saline rock is also expandable, and in the saturated environment, the expansion indicator of saline rock in the high salt content section is generally higher than the indicator in the non-saline section and low salt content section. In tunnel construction, targeted prevention and control measures should be taken to avoid the occurrence of engineering defects.
Abstract：
Saline rock is extremely unfavorable to tunnel engineering. In this study, based on a tunnel passing through thick chloride saline rock on the China-Laos Railway, its engineering geological characteristics are studied.Firstly, the saline rock engineering section is divided into the low salt content section and the high salt content section based on salt content. Then, the sections with different salt contents are tested using thin section identification,X-ray diffraction, strength test, water quality analysis, corrosion and expansibility tests to quantitatively study their physical, mechanical, hydrochemical, corrosion and expansibility and other engineering geological characteristics.The results indicate that the mineral components of the saline rock in this section is mainly rock salt (NaCl). The compressive strength of saline rock in the high salt content section is significantly lower than that of saline rock in the low salt content section. The main anions and cations in the groundwater come from the dissolution of salt, and as the salt content increases, the environmental action level of the groundwater gradually increases. Saline rock is corrosive, and the maximum upper corrosion rate in the high salt content section is 8.846~10.540 mm/h, with an average of 9.527 mm/h. Saline rock is also expandable, and in the saturated environment, the expansion indicator of saline rock in the high salt content section is generally higher than the indicator in the non-saline section and low salt content section. In tunnel construction, targeted prevention and control measures should be taken to avoid the occurrence of engineering defects.
CHEN Wei1,
2 ZHANG Minghong2 ZHANG Ying2 LIN Ling2
.Study on Engineering Geological Characteristics of Saline Rock in a Tunnel on China-Laos Railway[J] MODERN TUNNELLING TECHNOLOGY, 2023,V60(5): 234-242
2023, Vol. 60 