Abstract To solve the problem of softening and strength decrease of tertiary mudstone due to groundwater conver?
gence and excavation disturbance during the inverted arch construction of a tunnel, the laboratory test is carried out by field sampling. The results show that the uniaxial compressive strength of the tertiary mudstone in the natural state is negative correlated with the water content, the uniaxial compressive strength of the mudstone in the saturated state is obviously reduced with obvious softening effect, and the bearing capacity of the foundation after softening cannot meet the design requirements. In view of this, the water flows in different paths are classified and collected to reduce their deterioration effect on the surrounding rocks during the construction. The measures such as backfilling of the base with gravels and grouting reinforcement can solve the problems of seepage channel and surrounding rocks softening due to excavation disturbance of inverted arch, and the problem of insufficient bearing capacity of foundation is also effectively solved through the grouting reinforcement in the later period. Moreover, the indepen?
dent vertical and horizontal drainage systems are added in the water-rich sections, so that the water accumulated in the base of the inverted arch can be drained in time when the pressure condition is met, thus avoiding the possible basement diseases caused by bedrock softening due to the effect of groundwater after operation.
Abstract：
To solve the problem of softening and strength decrease of tertiary mudstone due to groundwater conver?
gence and excavation disturbance during the inverted arch construction of a tunnel, the laboratory test is carried out by field sampling. The results show that the uniaxial compressive strength of the tertiary mudstone in the natural state is negative correlated with the water content, the uniaxial compressive strength of the mudstone in the saturated state is obviously reduced with obvious softening effect, and the bearing capacity of the foundation after softening cannot meet the design requirements. In view of this, the water flows in different paths are classified and collected to reduce their deterioration effect on the surrounding rocks during the construction. The measures such as backfilling of the base with gravels and grouting reinforcement can solve the problems of seepage channel and surrounding rocks softening due to excavation disturbance of inverted arch, and the problem of insufficient bearing capacity of foundation is also effectively solved through the grouting reinforcement in the later period. Moreover, the indepen?
dent vertical and horizontal drainage systems are added in the water-rich sections, so that the water accumulated in the base of the inverted arch can be drained in time when the pressure condition is met, thus avoiding the possible basement diseases caused by bedrock softening due to the effect of groundwater after operation.
ZHANG Xianwei1 HONG Kairong2 CHANG Xiang2 CHEN Hong1
.Study on Engineering Characteristics of Tertiary Mudstone and Construction
Technology of Inverted Arch[J] MODERN TUNNELLING TECHNOLOGY, 2021,V58(2): 214-219
2021, Vol. 58 