Concrete face rockfill dam soft foundation reinforcing structure and construction method

Abstract

The invention discloses a concrete face rockfill dam soft foundation reinforcing structure and a construction method. The concrete face rockfill dam soft foundation reinforcing structure comprises a geogrid reinforced cushion layer, a geocell reinforced cushion layer and gravel piles which are arranged in a dam body; the top ends of the gravel piles are fixedly wrapped with composite geotextiles, and the gravel piles extend into a soft foundation; a dam body filler is arranged on the top layer of the soft foundation; and a concrete face is arranged on the surface layer of the dam body filler, the bottom end of the concrete face is connected with a concrete connecting plate, a concrete anti-seepage wall is arranged at the bottom of the tail end of the concrete connecting plate and extends into the soft foundation, and an anti-seepage curtain is arranged at the bottom of the concrete anti-seepage wall. The differential settlement deformation of the earth and rockfill dam can be effectively controlled, the possibility of foundation liquefaction is reduced, and the stability of the earth and rockfill dam is improved.

Description

technical field [0001] The invention belongs to the technical field of geotechnical engineering, and in particular relates to a weak foundation structure and a construction method for strengthening concrete face rockfill dams. Background technique [0002] Deep overburdens are widely distributed in Southwest China, and have the characteristics of diverse causes, variable thickness, complex composition and large differences in engineering characteristics. Building dams on deep overburden faces many problems, among which foundation settlement and uneven subsidence are one of them. In the construction of hydropower projects, it is necessary to adopt certain engineering and technical measures to carry out necessary treatment on the foundation to improve the bearing capacity and deformation resistance of the foundation. [0003] At present, the methods of foundation reinforcement for deep overburden include vibro-rock gravel piles, consolidation grouting, underground diaphragm w...

AI Technical Summary

Problems solved by technology

In foundations with deep overburden layers, sandy soil layers often appear. Under the conditions of water saturation and vibration external force, the pore water pressure in the sandy soil layer rises, causing the soil to liquefy and become unstable and destroyed, which in turn causes large deformation or uneven settlement. , the current anti-liquefaction treatment measures include pressure, dynamic compaction, consolidation grouting, etc. Although these measures can reduce the probability of soil liquefaction to a certain extent, they are not economical and are difficult to achieve in a long period of time. Anti-liquefaction effect

Geosynthetics have the functions of reinforcement, anti-seepage, reverse filtration, etc., and the construction is simple, green and environmentally friendly, and the cost is economical. Combining geosynthetics with existing foundation treatment methods can achieve a good reinforcement effect and reduce the unfavorable Uniform settlement deformation, however, geosynthetics are rarely used in deep overburden foundation reinforcement

[0004] Invention patent CN112195910A provides a soft foundation treatment structure and construction method of an earth-rockfill dam reinforced with vibratory crushed stone piles and rockfill body. The most important is stainless steel reinforcement or flat steel reinforcement. This type of reinforcement is prone to corrosion, and it is difficult to coordinate deformation with the rockfill material. The reinforcement spacing is set at 0.5m~1.0m, so that the reinforcement cannot fully play the role of the cushion , the stress diffusion effect is not good, and it cannot effectively reduce the force exerted by the dam filling on the foundation soil

[0005] The existing foundation reinforcement methods cannot well control the uneven settlement and deformation of the dam, and do not make full use of the reinforcement and filter effects of geosynthetics

Using gravel piles alone for foundation treatment, under the condition of long-term drainage, the pores between the aggregates inside the gravel piles are easily blocked, which affects the drainage and consolidation of the foundation soil, thereby increasing the possibility of liquefaction of the soil

In addition, at present, to control the deformation of the dam, it mainly only strengthens the foundation, and seldom takes corresponding measures from the perspective of optimizing the stress exerted by the dam on the foundation.

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