【Daily Discussion】Public Utilities – Water Resources and Hydropower – 20210516
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Briefly describe the objectives, principles, and measures for treating the gravel foundation of earth-rock dams. Answer: When an earth-rock dam is 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. Generally speaking, the treatment of sandy gravel foundations focuses on addressing the issue of seepage prevention; by adopting a combination of measures to block from above and drain from below, it is possible to control seepage in the foundation. The basic methods for controlling seepage in earth-rock dams include vertical impermeabilization, horizontal impermeabilization, and drainage for pressure reduction. The first two reflect the basic principle of \"blocking from above,\" while the latter reflects the basic principle of \"removing from below.\" For vertical seepage control, basic methods such as clay water stop channels, concrete water stop walls, concrete seepage barriers, cement-clay grouting curtains, and high-pressure jet grouting can be employed, while horizontal seepage control commonly makes use of seepage control linings. We welcome active participation in discussions; the system offers generous rewards for answering questions from VIP members! ! !
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 barriers are generally constructed using cohesive soil materials 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. Generally speaking, the treatment of sandy gravel foundations focuses on addressing the issue of seepage prevention; by adopting a combination of measures to block from above and drain from below, it is possible to control seepage in the foundation. The basic methods for controlling seepage in earth-rock dams include vertical impermeabilization, horizontal impermeabilization, and drainage for pressure reduction. The first two reflect the basic principle of \"blocking from above,\" while the latter reflects the basic principle of \"removing from below.\" For vertical seepage control, basic methods such as clay water stop channels, concrete water stop walls, concrete seepage barriers, cement-clay grouting curtains, and high-pressure jet grouting can be employed, while horizontal seepage control commonly 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 cutoffs, concrete anti-seepage walls, grouting curtains ； ??? (2) Horizontal impermeability: Lining ； Horizontal impermeable barriers are generally constructed using cohesive soil materials 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.
The bearing capacity of gravelly soil foundations is generally sufficient, and their compressibility is low. Therefore, when building a dam on a gravelly foundation, the main focus is on controlling seepage, by ensuring proper impermeabilization and drainage. Measures: (1) Vertical impermeability barriers, including clay water retaining walls, concrete impermeable walls, grouting curtains, etc ； (2) Upstream horizontal impermeable cover ； (3) Downstream drainage measures, including horizontal drainage layers, drainage ditches, pressure reduction wells, and permeable cover weights. These facilities can be used individually, or H can be used in combination
Answer: When an earth-rock dam is 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. Generally speaking, the treatment of sandy gravel foundations focuses on addressing the issue of seepage prevention; by combining measures of ‘blocking from above’ and ‘draining from below’, it is possible to control seepage in the foundation. The basic methods for controlling seepage in earth-rock dams include vertical impermeabilization, horizontal impermeabilization, and drainage for pressure reduction. The first two reflect the basic principle of \"blocking from above,\" while the latter reflects the basic principle of \"displacing downward.\" For vertical seepage control, basic methods such as clay cut-off grooves, concrete cut-off walls, concrete seepage barriers, cement-clay grouting curtains, and high-pressure jet grouting can be employed, while horizontal seepage control usually makes use of seepage control linings
The purpose is to give it higher shear resistance and load-bearing capacity； Principle: The treatment of such foundations focuses on seepage control. Common anti-seepage and drainage measures include: (1) Vertical anti-seepage: clay water cutoffs, concrete anti-seepage walls, grouting curtains ； (2) Horizontal impermeabilization: Lining ； Horizontal impermeable barriers are generally constructed using cohesive soil materials 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. Generally speaking, the treatment of sandy gravel foundations focuses on addressing the issue of seepage prevention; by adopting a combination of measures to block from above and drain from below, it is possible to control seepage in the foundation. The basic methods for controlling seepage in earth-rock dams include vertical impermeabilization, horizontal impermeabilization, and drainage for pressure reduction. The first two reflect the basic principle of \"blocking from above,\" while the latter reflects the basic principle of \"removing from below.\" For vertical seepage control, basic methods such as clay water-stop grooves, concrete water-stop walls, concrete seepage barriers, cement-clay grouting curtains, and high-pressure jet grouting can be employed, while horizontal seepage control commonly makes use of seepage-proof 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. Generally speaking, the treatment of sandy gravel foundations focuses on addressing the issue of seepage prevention; by adopting a combination of measures to block from above and drain from below, it is possible to control seepage in the foundation. The basic methods for controlling seepage in earth-rock dams include vertical impermeabilization, horizontal impermeabilization, and drainage for pressure reduction. The first two reflect the basic principle of \"blocking from above,\" while the latter reflects the basic principle of \"removing from below.\" For vertical seepage control, basic methods such as clay water stop channels, concrete water stop walls, concrete seepage barriers, cement-clay grouting curtains, and high-pressure jet grouting can be employed, while horizontal seepage control commonly 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. Generally speaking, the treatment of sandy gravel foundations focuses on addressing the issue of seepage prevention; by adopting a combination of measures to block from above and drain from below, it is possible to control seepage in the foundation. The basic methods for controlling seepage in earth-rock dams include vertical impermeabilization, horizontal impermeabilization, and drainage for pressure reduction. The first two reflect the basic principle of \"blocking from above,\" while the latter reflects the basic principle of \"removing from below.\" For vertical seepage control, basic methods such as clay water stop channels, concrete water stop walls, concrete seepage barriers, cement-clay grouting curtains, and high-pressure jet grouting can be employed, while horizontal seepage control commonly 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.