Artificial composite foundation for building clay core rock-fill dam on deep overburden and construction method for artificial composite foundation

Abstract

The invention provides an artificial composite foundation for building a clay core rock-fill dam on a deep overburden. The artificial composite foundation comprises a base rock (1) and an overburden (2) arranged on the base rock (2); a filter layer (5) is arranged at the outer side of a reversed filter layer (4); a rock-fill (6) is arranged at the outer side of the filter layer (5); the rock-fill (6), the filter layer (5), the reversed filter layer (4) and a core (3) form a dam body, wherein the thickness of the overburden (2) is more than 50m; a concrete cover board (7) is arranged in the overburden (2); and the height of the dam body is more than 150m. The shortages of large digging work amount, increased scale of river diversion works, increased scale of waste slag field, prolonged engineering construction period and increased engineering investment are avoided by using the artificial composite foundation. According to the artificial composite foundation, the diaphragm wall construction and the reinforcing grouting construction are conducted in gallery of the concrete cover board, and the dam filling construction can be synchronously performed, so that the construction period is shortened effectively. The invention simultaneously discloses a construction method for the artificial composite foundation.

Description

technical field [0001] The invention belongs to the technical field of water conservancy and hydropower engineering. More specifically, it is an artificial composite foundation for building a clay (core wall) rockfill dam on a deep covering layer (thickness greater than 50m). A construction method for building an artificial composite foundation of a rockfill dam with a clay core wall on a layer. Background technique [0002] Clay core rockfill dams (including gravel soil core rockfill dams) are widely used in hydropower projects at home and abroad. With the development of hydropower projects in Southwest my country, which is rich in water resources, it involves There are more and more hydropower projects building high clay core rockfill dams on the upper layer, and the scale is also increasing. The utilization and treatment of the deep overburden of the river bed is related to the safety and economy of the project. At the same time, it has a major impact on the dam site, dam...

AI Technical Summary

Problems solved by technology

[0004] Excavating all the deep overburden by adopting plan (1) will often bring many adverse effects, such as the high slope of foundation pit excavation will affect the stability of cofferdam and foundation pit slope, the standard of diversion project will be improved, the scale will be enlarged, The layout is difficult, the excavation of the overburden is large, the spoil site is large in scale, the layout is difficult, the project investment increases, and the construction period is extended, etc.

[0005] Using the scheme (2) to retain the deep overburden and use concrete cut-off walls for anti-seepage treatment, the technical reliability needs to be improved. The problems faced by building a rockfill dam with a clay core wall on a deep overburden are more difficult than building a dam on bedrock It is more complicated. Under the action of dam filling load and water pressure, the overburden will produce large settlement and uneven settlement. With the increase of overburden depth and dam scale, the deformation between the core wall and the dam shell is uncoordinated. , the deformation between the core wall and the anti-seepage wall is not coordinated, the stress and deformation properties of the anti-seepage wall are poor, and the concentrated leakage at the joint between the core wall and the anti-seepage wall is more prominent, and it is easy to crack the core wall, break the anti-seepage wall, and The joints of the wall and the cut-off wall are disengaged, and even the dam body and the covering layer have seepage damage, which affects the safe operation of the dam, such as image 3 shown

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