【Daily Discussion】Public Utilities – Water Resources and Hydropower – 20210120

When earth-rock dams are built on a sandy-gravel foundation, the bearing capacity of the foundation is usually sufficient, and the settlement caused by compression of the foundation is generally not significant. The treatment of sand-gravel foundations primarily focuses on addressing the issue of seepage control; by adopting measures that combine upper sealing and lower drainage, it is possible to manage the seepage in such foundations. The main seepage control measures include basic types such as clay water cut-off grooves, concrete water cut-off walls, concrete seepage control walls, cement-clay grouting curtains, and high-pressure jet grouting; horizontal seepage control typically makes use of seepage control linings.

Characteristics of gravelly soil foundations: they possess high shear strength and bearing capacity, exhibit minimal compressional deformation, but have poor impermeability; therefore, the treatment of such foundations focuses on controlling seepage. Common anti-seepage and drainage measures include: (1) Vertical anti-seepage: clay water stop walls, concrete anti-seepage walls, grouting curtains ； (2) Horizontal impermeabilization: Lining ； Horizontal impermeable structures are generally constructed using cohesive soil to form a horizontal layer that connects with the dam’s impermeable core, extending upstream to the required length. (3) Install drainage and pressure reduction facilities downstream. When there is a permeable layer beneath the dam foundation at a shallow depth, drainage ditches can be installed at the downstream toe of the dam. When the permeable layer beneath the dam foundation is buried deep and the foundation has a stratified structure, pressure relief wells can be installed at the downstream toe of the dam to effectively remove seepage and reduce the uplift force on the dam foundation.

When earth-rock dams are built on a sandy-gravel foundation, the bearing capacity of the foundation is usually sufficient, and the settlement caused by compression of the foundation is generally not significant. The treatment of sand-gravel foundations primarily focuses on addressing the issue of seepage control; by adopting measures that combine upper sealing and lower drainage, it is possible to manage the seepage in such foundations. The main seepage control measures include basic types such as clay water cut-off grooves, concrete water cut-off walls, concrete seepage control walls, cement-clay grouting curtains, and high-pressure jet grouting; horizontal seepage control typically makes use of seepage control linings.

When earth-rock dams are built on a sandy-gravel foundation, the bearing capacity of the foundation is usually sufficient, and the settlement caused by compression of the foundation is generally not significant. The treatment of sand-gravel foundations primarily focuses on addressing the issue of seepage control; by adopting measures that combine upper sealing and lower drainage, it is possible to manage the seepage in such foundations. Common anti-seepage and drainage measures include: (1) Vertical anti-seepage: clay water stop walls, concrete anti-seepage walls, grouting curtains ； (2) Horizontal impermeabilization: Lining ； Horizontal impermeable structures are generally constructed using cohesive soil to form a horizontal layer that connects with the dam’s impermeable core, extending upstream to the required length. (3) Install drainage and pressure reduction facilities downstream. When there is a permeable layer beneath the dam foundation at a shallow depth, drainage ditches can be installed at the downstream toe of the dam. When the permeable layer beneath the dam foundation is buried deep and the foundation has a stratified structure, pressure relief wells can be installed at the downstream toe of the dam to effectively remove seepage and reduce the uplift force on the dam foundation.

When earth-rock dams are built on a sandy-gravel foundation, the bearing capacity of the foundation is usually sufficient, and the settlement caused by compression of the foundation is generally not significant. The treatment of sand-gravel foundations primarily focuses on addressing the issue of seepage control; by adopting measures that combine upper sealing and lower drainage, it is possible to manage the seepage in such foundations. The main seepage control measures include basic types such as clay water cut-off grooves, concrete water cut-off walls, concrete seepage control walls, cement-clay grouting curtains, and high-pressure jet grouting; horizontal seepage control typically makes use of seepage control linings.

When earth-rock dams are built on a sandy-gravel foundation, the bearing capacity of the foundation is usually sufficient, and the settlement caused by compression of the foundation is generally not significant. The treatment of sand-gravel foundations primarily focuses on addressing the issue of seepage control; by adopting measures that combine upper sealing and lower drainage, it is possible to manage the seepage in such foundations. The main seepage control measures include basic types such as clay water cut-off grooves, concrete water cut-off walls, concrete seepage control walls, cement-clay grouting curtains, and high-pressure jet grouting; horizontal seepage control typically makes use of seepage control linings.

When earth-rock dams are built on a sandy-gravel foundation, the bearing capacity of the foundation is usually sufficient, and the settlement caused by compression of the foundation is generally not significant. The treatment of sand-gravel foundations primarily focuses on addressing the issue of seepage control; by adopting measures that combine upper sealing and lower drainage, it is possible to manage the seepage in such foundations. Common anti-seepage and drainage measures include: (1) Vertical anti-seepage: clay water-stop trenches, concrete anti-seepage walls, grouting curtains ； (2) Horizontal impermeabilization: Lining ； Horizontal impermeable structures are generally constructed using cohesive soil to form a horizontal layer that connects with the dam’s impermeable core, extending upstream to the required length. (3) Install drainage and pressure reduction facilities downstream. When there is a permeable layer beneath the dam foundation at a shallow depth, drainage ditches can be installed at the downstream toe of the dam. When the permeable layer beneath the dam foundation is buried deep and the foundation has a stratified structure, pressure relief wells can be installed at the downstream toe of the dam to effectively remove seepage and reduce the uplift force on the dam foundation.

When earth-rock dams are built on a sandy-gravel foundation, the bearing capacity of the foundation is usually sufficient, and the settlement caused by compression of the foundation is generally not significant. The treatment of sand-gravel foundations primarily focuses on addressing the issue of seepage control; by adopting measures that combine upper sealing and lower drainage, it is possible to manage the seepage in such foundations. Common anti-seepage and drainage measures include: (1) Vertical anti-seepage: clay water-stop trenches, concrete anti-seepage walls, grouting curtains ； (2) Horizontal impermeabilization: Lining ； Horizontal impermeable structures are generally constructed using cohesive soil to form a horizontal layer that connects with the dam’s impermeable core, extending upstream to the required length. (3) Install drainage and pressure reduction facilities downstream. When there is a permeable layer beneath the dam foundation at a shallow depth, drainage ditches can be installed at the downstream toe of the dam. When the permeable layer beneath the dam foundation is buried at a great depth and the foundation has a stratified structure, pressure relief wells can be installed at the downstream foot of the dam to effectively remove seepage water and reduce the uplift force on the dam foundation