CN111206543A - Construction method of dam in hydraulic and hydroelectric engineering - Google Patents
Construction method of dam in hydraulic and hydroelectric engineering Download PDFInfo
- Publication number
- CN111206543A CN111206543A CN202010192824.9A CN202010192824A CN111206543A CN 111206543 A CN111206543 A CN 111206543A CN 202010192824 A CN202010192824 A CN 202010192824A CN 111206543 A CN111206543 A CN 111206543A
- Authority
- CN
- China
- Prior art keywords
- parts
- layer
- dam
- concrete
- roller compacted
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
Links
Classifications
-
- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02B—HYDRAULIC ENGINEERING
- E02B7/00—Barrages or weirs; Layout, construction, methods of, or devices for, making same
- E02B7/02—Fixed barrages
- E02B7/04—Dams across valleys
- E02B7/06—Earth-fill dams; Rock-fill dams
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B28/00—Compositions of mortars, concrete or artificial stone, containing inorganic binders or the reaction product of an inorganic and an organic binder, e.g. polycarboxylate cements
- C04B28/02—Compositions of mortars, concrete or artificial stone, containing inorganic binders or the reaction product of an inorganic and an organic binder, e.g. polycarboxylate cements containing hydraulic cements other than calcium sulfates
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B2111/00—Mortars, concrete or artificial stone or mixtures to prepare them, characterised by specific function, property or use
- C04B2111/74—Underwater applications
Abstract
The invention discloses a construction method of a dam in water conservancy and hydropower engineering, wherein a rock-fill dam comprises an upstream paving area, a panel layer, a cushion layer, a transition layer and a rock-fill area; the construction method of the face slab rock-fill dam comprises the steps of cleaning a dam abutment and a foundation pit, pouring concrete to form an upstream paving area and a base, pouring a rock-fill area on the base, wherein the rock-fill area is formed by repeatedly pouring and rolling multiple layers of roller compacted concrete; and sequentially filling a panel layer, a cushion layer and a transition layer from upstream to downstream on the rockfill area. The stone needed in the process of the concrete faced rockfill dam can be obtained by directly excavating and screening the dam foundation or the dam abutment, can be obtained according to local conditions, saves the cost, reduces the transportation energy consumption, and is more environment-friendly and energy-saving.
Description
Technical Field
The invention relates to the technical field of engineering construction, in particular to a construction method of a dam in water conservancy and hydropower engineering.
Background
In water conservancy and hydropower engineering, a dam body is one of important construction projects. The dam can be divided into a concrete dam and an earth-rock dam; concrete dams generally refer to dams formed by pouring (or rolling) concrete or assembling precast concrete blocks, earth and rockfill dams generally refer to retaining dams formed by piling, filling, rolling and the like local earth materials, stone materials or mixed materials, and when dam materials mainly comprise soil and gravel, the retaining dams are called as earth dams, and when stone slag, pebbles and blasting stone materials are mainly called as rockfill dams. In the prior art, the main body of the water conservancy and hydropower dam is generally constructed by adopting a dam construction method.
In 1993, greek built the world's first cemented sand gravel dam, Marathia dam, and this new damming technology has been rapidly developed in japan since the 90 s of the 20 th century. The core content of the technology is as follows: the method is characterized in that a proper amount of cement is added into local natural sandstone materials to be directly used for damming. The damming technology brings remarkable effects that: greatly reduces the damming cost, is environment-friendly, and has high efficiency and high speed in construction.
The dam mainly comprises three parts: seepage-proofing panel, seepage-proofing ground structure and rockfill dam body. The seepage-proofing panel is a seepage-proofing part of the rock-fill dam, and the panel is connected with the seepage-proofing grounding structure through a peripheral seam. The seepage-proofing grounding structure mainly controls seepage of the foundation and the dam foundations of the two banks and reduces seepage. The rockfill dam body is a main component of the dam, is also a supporting structure of the panels, and is used for safely draining water leakage of the panels and joints thereof.
The construction period of the dam is determined according to the project amount, and generally, the height of the dam in the existing hydraulic and hydroelectric project is mostly more than 100 meters, even can reach 300 meters. The casting thickness of the single-layer concrete of the dam is generally below 1 meter, so that the required height can be achieved only by repeatedly casting roller compacted concrete layer by layer in the construction process of the dam. For example, in the chinese invention patent application CN 2016565528, it discloses an ultra-high rockfill dam structure suitable for hydraulic and hydroelectric engineering, the rockfill dam comprises a crushed rock concrete base, a rockfill dam body and a concrete anti-seepage panel, the crushed rock concrete base is a base with a height of 90m-110m formed by multiple layers of crushed rock concrete layers through vibration and rolling, each layer of crushed rock concrete layer is formed by lower concrete, middle rock and upper concrete through vibration and rolling, the lower concrete of each layer of crushed rock concrete layer is made of secondary concrete, the concrete slump is 70 mm-150 mm, and the sand and stone of the lower concrete is made of sand and stone with a diameter of 0-5 mm, 5-20 mm and 20-40 mm dug at a construction site; the upper concrete adopts first-level rolled concrete, the VC value of the concrete is 1-5 s, and the grit material of the upper concrete adopts grit material with the diameter of 0-5 mm and 5-20 mm dug in a construction site; the middle layer block stone is a block stone or a pebble with the diameter of more than 40mm dug in a construction site; the concrete anti-seepage panel is formed by pouring concrete at the upper reaches of the piled stone-rolled block concrete base and the rock-fill dam body.
It can be seen from the disclosure of the above patent that the base has a height of about 100m and is formed by vibration rolling of multiple layers of rolled block stone concrete.
The roller compacted concrete is a main pouring material of the dam, and the material components, the construction process and the like of the roller compacted concrete can influence the structure and the performance of the main body of the rock-fill dam. For example, patent CN 108439867 a discloses a rock-fill dam using a seamless panel, which comprises a seamless panel made of cement, fine sand, secondary fly ash, polyvinyl alcohol fiber, waterproof emulsion and water reducing agent, wherein each cubic meter of the seamless panel contains 550-560 kg of cement, 460-550 kg of fine sand, 650-690 kg of secondary fly ash, 24-28 kg of polyvinyl alcohol fiber, 10-12 kg of waterproof emulsion and 20-24 kg of water reducing agent. Patent CN 103253898B discloses a method for preparing roller compacted concrete for dams, wherein the weight proportions of the components of the roller compacted concrete are respectively as follows: 60 parts of water, 55 parts of cement, 70 parts of fly ash, 500 parts of crushed finished river sand, 1400 parts of coarse aggregate, 0.876 part of retarding superplasticizer and 0.02 part of air entraining agent; the coarse aggregate comprises the following components by weight: and (3) medium stone: large stone 30:40: 30.
It can be seen from the prior art that the dam is usually constructed by adopting roller compacted concrete through multi-layer repeated pouring, in the construction process, because the roller compacted concrete between layers needs to be poured before the initial setting is reached, otherwise, if the roller compacted concrete of the lower layer is coagulated and then the roller compacted concrete of the upper layer is poured, the layering phenomenon can occur, so that the bonding force between the layers is reduced, and the serious quality problem is caused. In order to solve the problems, in the prior art, a proper amount of retarder is usually added into concrete, and the cement retarder is an additive which can delay the hydration reaction of cement, so that the setting time of the concrete is prolonged, the fresh concrete keeps plasticity for a long time, the pouring is convenient, the construction efficiency is improved, and meanwhile, various performances of the concrete in the later period cannot be adversely affected. Retarders are various in types, and the main commonly used retarders are: lignosulfonate and derivatives thereof, low molecular weight cellulose and derivatives thereof, hydroxycarboxylic acid (salts), organic phosphonic acid (salts), boric acid (salts), complexes and the like.
Meanwhile, in order to reduce the use of water, a water reducing agent is generally added into concrete, and the compounding of the water reducing agent and a retarder is a common technical means. However, the performance influence of different water reducing agents and retarders on concrete after compounding is different, and when the mixing amount of the retarders is different, the influence on the concrete is also different.
For example, the retarder has a certain influence on the durability of concrete, and when the retarder and the polycarboxylic acid type high-efficiency water reducing agent form a composite agent, the retarder has a certain influence on the chloride ion permeability resistance of the concrete. The literature reports that when the polycarboxylic acid high-efficiency water reducing agent is combined with different types of retarders, the diffusion coefficients of chloride ions are different, and the permeability resistance is different; in addition, the mixing amount of the retarder is different, and the penetration resistance is also different, and in most cases, the penetration resistance is reduced after the amount of the retarder is increased, for example. When the carboxylic acid high-efficiency water reducing agent is compounded with sodium tripolyphosphate, the anti-penetration capability is good at 0.25 percent of the mixing amount, and is seriously reduced at 0.45 percent of the mixing amount.
The anti-permeability is one of important indexes for measuring the durability of the rock-fill dam body, and when the anti-permeability of the dam body is reduced, the dam is more easily infiltrated by upstream water, so that the internal structural strength of the dam is easily reduced. Because the water content is not dried in the early stage of concrete construction, the anti-permeability capability is mainly used for detecting the anti-permeability capability of the dam after construction.
Therefore, in the reasonable mixing amount range of the retarder, how to select a proper retarder and a polycarboxylic acid high-efficiency water reducing agent combination can obviously reduce the diffusion coefficient of concrete chloride ions and greatly improve the anti-permeability performance of the concrete, and meanwhile, the dosage of the retarder can not influence the anti-permeability performance, so that the retarder is a problem to be solved in the prior art.
Disclosure of Invention
The invention aims to provide a construction method of a dam in water conservancy and hydropower engineering. Meanwhile, the dosage of the retarder does not cause negative influence on the anti-permeability performance within the doping amount range of the retarder.
In order to achieve the above object, an embodiment of the present invention provides a method for constructing a dam in hydraulic and hydroelectric engineering, wherein the rock-fill dam comprises an upstream paving area, a face layer, a cushion layer, a transition layer and a rock-fill area; the construction method of the dam comprises the following steps:
A. clearing dam shoulders and a foundation pit, excavating dam shoulder parts of two banks before closure according to the diversion flood-crossing requirement, and excavating a foundation pit part of a riverbed after closure; removing the covering layer of the dam abutment and the soft soil layer of the foundation pit, and removing accumulated water and impurities; moving earthwork obtained by cleaning, blasting and excavating to a slag yard to screen out stones;
B. arranging reinforcing steel bars in the foundation pit, and pouring concrete to form an upstream paving area; pouring rich-grout cemented gravel concrete in the foundation pit to form a base, and arranging an impermeable layer structure between the base and an upstream paving area for impermeable treatment;
C. pouring a rockfill area on the base, wherein the rockfill area is formed by repeatedly pouring and rolling multiple layers of roller compacted concrete; the pouring method of the roller compacted concrete comprises the following steps:
c1: firstly, pouring lower-layer roller compacted concrete and leveling, and pouring upper-layer roller compacted concrete before the initial setting of the lower-layer roller compacted concrete; the thickness of the lower layer of roller compacted concrete is 20 cm-25 cm, and the thickness of the upper layer of roller compacted concrete is 30 cm-35 cm; leveling after the upper layer of roller compacted concrete is poured, and rolling by using a vibration roller before initial setting until the surface is uniformly grouted; repeating the step C1 until the height of the rockfill area reaches the design height;
D. and sequentially filling a panel layer, a cushion layer and a transition layer from upstream to downstream on the rockfill area.
In one of the optimization schemes of the invention, the slurry-rich cemented sand gravel concrete comprises 100 to 150 parts of water, 100 to 150 parts of cement, 80 to 150 parts of fly ash, 800 to 1200 parts of sand and 1000 to 1500 parts of gravel, and the particle size of aggregate is 10 to 20 cm.
In one of the optimization schemes of the invention, the vibration pressure of the vibration roller is 300 KN-500 KN; the walking speed is 1 km/h-2 km/h.
In one of the optimization schemes of the invention, the strength of the slurry-rich cemented gravel concrete is C20-C25.
In one of the optimized schemes of the invention, the lower layer roller compacted concrete comprises
100 parts of water; 70-80 parts of cement; 60-80 parts of secondary fly ash;
400-500 parts of medium sand;
300 to 400 portions of crushed stone with the diameter of 5 to 10 mm;
400-500 parts of crushed stone with the diameter of 10-20 mm;
0.05 to 0.1 portion of air entraining agent; 0.05 to 0.5 portion of polycarboxylic acid water reducing agent;
0.05 to 0.5 portion of retarder sodium carboxymethyl cellulose or sodium tripolyphosphate;
0.05 to 0.1 portion of quinoline carboxylic acid ethyl ester; 0.05 part to 0.1 part of 5-hydroxymethyl furfural.
In one of the optimized schemes of the invention, the upper layer of roller compacted concrete comprises
100 parts of water; 60-80 parts of cement; 60-80 parts of secondary fly ash;
400-500 parts of medium sand;
crushed stone with the diameter of 10 mm-20 mm: 300 to 400 portions;
crushed stone with the diameter of 20 mm-40 mm: 500-600 parts;
0.05 to 0.1 portion of air entraining agent; 0.05 to 0.5 portion of polycarboxylic acid water reducing agent;
0.05 to 0.5 portion of retarder sodium carboxymethyl cellulose or sodium tripolyphosphate;
0.05 to 0.1 portion of quinoline carboxylic acid ethyl ester; 0.05 part to 0.1 part of 5-hydroxymethyl furfural.
In one of the optimization schemes of the invention, the air entraining agent is acrylic epoxy resin.
In one of the optimized schemes of the invention, the lower layer roller compacted concrete comprises:
100 parts of water; 75 parts of cement; 70 parts of secondary fly ash; 500 parts of medium sand;
320 parts of crushed stone with the diameter of 8 mm; 500 parts of crushed stone with the diameter of 15 mm;
0.08 part of air entraining agent acrylic epoxy resin;
0.2 part of polycarboxylic acid water reducing agent; 0.4 part of retarder sodium carboxymethyl cellulose;
0.06 part of quinoline carboxylic acid ethyl ester; 0.05 part of 5-hydroxymethylfurfural;
the upper layer roller compacted concrete comprises:
100 parts of water; 75 parts of cement; 70 parts of secondary fly ash; 500 parts of medium sand;
340 parts of crushed stone with the diameter of 15 mm; 520 parts of crushed stone with the diameter of 32 mm;
0.08 part of air entraining agent acrylic epoxy resin;
0.2 part of polycarboxylic acid water reducing agent; 0.4 part of retarder sodium tripolyphosphate;
0.06 part of quinoline carboxylic acid ethyl ester; 0.05 part of 5-hydroxymethylfurfural.
In summary, the invention has the following advantages:
1. the stone needed in the dam process can be obtained by directly excavating and screening the dam foundation or the dam abutment, can be obtained according to local conditions, saves the cost, reduces the transportation energy consumption, and is more environment-friendly and energy-saving.
2. The retarder sodium carboxymethyl cellulose capable of being compounded with the polycarboxylic acid high-performance water reducing agent is selected, and two auxiliaries of ethyl quinolinecarboxylate and 5-hydroxymethylfurfural are added at the same time, and the two auxiliaries have the functions of eliminating the influence of a high-doping amount of retarder on the chloride ion diffusion performance of the dam, namely the influence on the anti-permeability capability of the dam body; the improvement of the anti-seepage capability can weaken the erosion action of water on the dam body, and is beneficial to the stability of the dam body.
Detailed Description
The invention discloses a construction method of a dam in water conservancy and hydropower engineering, wherein a rock-fill dam comprises an upstream paving area, a panel layer, a cushion layer, a transition layer and a rock-fill area; the construction method of the dam comprises the following steps:
A. clearing dam shoulders and a foundation pit, excavating dam shoulder parts of two banks before closure according to the diversion flood-crossing requirement, and excavating a foundation pit part of a riverbed after closure; removing the covering layer of the dam abutment and the soft soil layer of the foundation pit, and removing accumulated water and impurities; and moving earthwork obtained by cleaning, blasting and excavating to a slag yard to screen out stones.
In the step a, the construction process of cleaning and excavating the dam abutment and the foundation pit belongs to foundation engineering, and needs to be performed according to relevant steps, construction conditions and requirements, for example, the dam foundation and bank slope treatment can be performed by installing the following requirements and methods:
construction stipulation: the dam foundation, toe board foundation and bank slope treatment belong to concealed engineering and should be carefully constructed according to the design and specification requirements. Geologists should perform geological delineation, logging and arrangement faithfully and accurately in the processing process. When the bank slope is treated, measures such as intercepting and draining should be taken to prevent rainwater on the two bank slope from washing the cushion layer.
Excavating a dam foundation and a bank slope: the excavation of the foundation at the toe board part can be carried out in two steps. Firstly, the surface covering is peeled off according to the design line, and the exposed topographic and geological data are submitted to the design unit for reference when adjusting the position of the toe board or the axis of the dam. And finally, excavating the bedrock after line setting. The building base surface should meet the design requirements.
The slope after the rock bank slope is excavated and cleaned is in accordance with the design regulation. When the rock side slope at the toe board part has local reverse slope or pit, slope cutting or concrete filling treatment is carried out. The rock slope above the toe board has fast crack growth and weathering speed, and has need of adopting protection measures of spraying cement mortar or concrete, etc.
The weathered rock and sand gravel temporary excavation slope should meet the stability condition and the construction requirement.
And a grid lattice point sampling inspection or a digging and probing well inspection is arranged on a gravel layer reserved at the bottom of the rock-fill dam body. The reserved range and thickness are determined by the design unit according to the density and grading condition of the composite material. The surface layer of the part is kept and is compacted by a heavy vibration roller or a tamping plate before the dam body is filled.
And (3) bedrock seepage prevention treatment:
the treatment of the joints and cracks of the toe board part should be carried out according to the design requirements. When the design is not specified, the following method is preferably adopted: (1) when the rock is relatively complete and the crack is small, cleaning the joints and the filler in the crack, washing the joints and the filler, and pouring cement paste or cement mortar to block the joint according to the width of the crack; (2) when rock joints and cracks develop relatively and water seepage is serious, besides the treatment measures, a concrete cover plate is poured or sprayed on the rock surface of the pad zone at the downstream of the toe plate to cover, and a filter material is paved behind the concrete protection section.
Any fault or fracture zone that intersects the toe plate must be treated as designed. The consolidation grouting of the rock foundation and the grouting of the tent are carried out according to the following requirements: (1) grouting construction is carried out on the toe board after the concrete reaches the designed strength, and grouting holes are reserved in the toe board. (2) Grouting of underwater parts is completed before reservoir water storage. (3) Grouting pressure should be determined experimentally. The toe board must not be lifted during grouting.
B. Arranging reinforcing steel bars in the foundation pit, and pouring concrete to form an upstream paving area; pouring rich-grout cemented gravel concrete in the foundation pit to form a base, and arranging an impermeable layer structure between the base and an upstream paving area for impermeable treatment; the strength of the slurry-rich cemented gravel concrete is C20-C25. The upstream paving area has certain strength and seepage-proofing capacity, and a layer of seepage-proofing structure is arranged between the base and the upstream paving area to strengthen the seepage-proofing capacity.
C. Pouring a rockfill area on the base, wherein the rockfill area is formed by repeatedly pouring and rolling multiple layers of roller compacted concrete; the pouring method of the roller compacted concrete comprises the following steps:
c1: firstly, pouring lower-layer roller compacted concrete and leveling, and pouring upper-layer roller compacted concrete before the initial setting of the lower-layer roller compacted concrete; the thickness of the lower layer of roller compacted concrete is 20 cm-25 cm, and the thickness of the upper layer of roller compacted concrete is 30 cm-35 cm; leveling after the upper layer of roller compacted concrete is poured, and rolling by using a vibration roller until the surface is uniformly slurried before initial setting, wherein the vibration pressure of the vibration roller is 400 KN; the walking speed is 2 km/h; repeating the step C1 until the height of the rockfill area reaches the design height; the pouring height of the base can be set to be 5 m-10 m; each layer of the roller compacted concrete of the rockfill area consists of an upper layer of roller compacted concrete and a lower layer of roller compacted concrete, the total thickness of the upper layer and the lower layer is 50 cm-60 cm, and if the rockfill area with the height of 100 m-120 m needs to be poured, about 200 layers of roller compacted concrete are needed.
D. And sequentially filling a panel layer, a cushion layer and a transition layer from upstream to downstream on the rockfill area. The construction process of the panel layer, the cushion layer and the transition layer can be carried out according to the prior art.
In one optimized embodiment of the invention, the slurry-rich cemented sand gravel concrete comprises 100 to 150 parts of water, 100 to 150 parts of cement, 80 to 150 parts of fly ash, 800 to 1200 parts of sand and 1000 to 1500 parts of gravel, and the particle size of aggregate is 10 to 20 cm.
In one of the preferred embodiments of the present invention, the lower layer of roller compacted concrete comprises
100 parts of water; 70-80 parts of cement; 60-80 parts of secondary fly ash;
400-500 parts of medium sand;
300 to 400 portions of crushed stone with the diameter of 5 to 10 mm;
400-500 parts of crushed stone with the diameter of 10-20 mm;
0.05 to 0.1 portion of air entraining agent; 0.05 to 0.5 portion of polycarboxylic acid water reducing agent;
0.05 to 0.5 portion of retarder sodium carboxymethyl cellulose or sodium tripolyphosphate;
0.05 to 0.1 portion of quinoline carboxylic acid ethyl ester; 0.05 part to 0.1 part of 5-hydroxymethyl furfural.
In one of the preferred embodiments of the present invention, the upper layer of roller compacted concrete comprises
100 parts of water; 60-80 parts of cement; 60-80 parts of secondary fly ash;
400-500 parts of medium sand;
crushed stone with the diameter of 10 mm-20 mm: 300 to 400 portions;
crushed stone with the diameter of 20 mm-40 mm: 500-600 parts;
0.05 to 0.1 portion of air entraining agent; 0.05 to 0.5 portion of polycarboxylic acid water reducing agent;
0.05 to 0.5 portion of retarder sodium carboxymethyl cellulose or sodium tripolyphosphate;
0.05 to 0.1 portion of quinoline carboxylic acid ethyl ester; 0.05 part to 0.1 part of 5-hydroxymethyl furfural.
In one preferred embodiment of the present invention, the lower layer roller compacted concrete comprises:
100 parts of water; 75 parts of cement; 70 parts of secondary fly ash; 500 parts of medium sand;
320 parts of crushed stone with the diameter of 8 mm; 500 parts of crushed stone with the diameter of 15 mm;
0.08 part of air entraining agent acrylic epoxy resin;
0.2 part of polycarboxylic acid water reducing agent; 0.4 part of retarder sodium carboxymethyl cellulose;
0.06 part of quinoline carboxylic acid ethyl ester; 0.05 part of 5-hydroxymethylfurfural;
the upper layer roller compacted concrete comprises:
100 parts of water; 75 parts of cement; 70 parts of secondary fly ash; 500 parts of medium sand;
340 parts of crushed stone with the diameter of 15 mm; 520 parts of crushed stone with the diameter of 32 mm;
0.08 part of air entraining agent acrylic epoxy resin;
0.2 part of polycarboxylic acid water reducing agent; 0.4 part of retarder sodium tripolyphosphate;
0.06 part of quinoline carboxylic acid ethyl ester; 0.05 part of 5-hydroxymethylfurfural.
Experiment for influence of compounding of polycarboxylic acid water reducing agent and different retarders on initial setting time of concrete
1.1, experimental materials:
the blank group comprises the following components:
100 parts of water; 75 parts of cement; 70 parts of secondary fly ash; 500 parts of medium sand;
320 parts of crushed stone with the diameter of 8 mm; 500 parts of crushed stone with the diameter of 15 mm;
0.08 part of air entraining agent acrylic epoxy resin; 0.2 part of polycarboxylic acid water reducing agent.
Examples the components of each group were increased on a blank basis.
1.2, an initial setting time detection method: a cement standard setting time detector can be used, and the instrument meets the requirements of GB/T1346-2001 (a cement standard consistency, setting time and stability test method) and JC/T727-2005 'cement paste standard consistency and setting time tester'. The specific operation method is as follows:
preparation work before measurement: and adjusting a test needle of the coagulation time measuring instrument to contact the bottom plate, so that the pointer is aligned to the zero point.
Preparation of test pieces: the model is filled once with pure pulp with standard consistency prepared by water consumption of standard consistency according to 5.2, vibrated for several times and strickleed off, and immediately put into a moisture curing box.
Initial setting time measurement: (1) the time from the time when the cement is completely added into the water to the initial setting state is recorded as the initial setting time and is measured in min. (2) The test piece is maintained in a moisture curing box until 30min after water is added, and the first measurement is carried out. During measurement, the test mold is taken out of the moisture curing box and placed below the test needle, and the contact between the test needle and the surface of the cement paste is reduced. After the screws are screwed for 1-2 s, the screws are suddenly loosened, so that the test rod is vertically and freely sunk into the cement paste. The reading of the pointer at which the test needle stopped sinking or released the test needle for 30s was observed. (3) The measurement was performed every 5min near the initial setting. When the test needle sinks to 4mm +/-1 mm from the bottom plate, the cement reaches an initial setting state. (4) The measurement should be repeated once immediately after the initial setting is reached, and the initial setting state can be determined only when the two conclusions are the same.
1.3 the formulation of each component and the experimental results are shown in the following table 1:
table 1: initial setting time experimental results:
| group of | Additive agent | Amount of addition | Initial setting time (h) | Initial setting for prolonged time |
| Blank group | - | - | 6.8 | - |
| Example 11 | Sodium gluconate | 0.4 portion of | 10.3 | 3.5 |
| Example 12 | Lignosulfonate salts | 0.4 portion of | 11.5 | 4.3 |
| Example 13 | Sugar calcium | 0.4 portion of | 8.9 | 2.1 |
| Example 14 | Sodium carboxymethylcellulose | 0.4 portion of | 13.8 | 6.0 |
| Example 15 | Tripolyphosphoric acidSodium salt | 0.4 portion of | 14.6 | 7.8 |
In general, the initial setting time of the concrete is generally 2-4 h when no polycarboxylic acid high-performance water reducing agent is added. From the above experiment, it can be seen that the addition of the polycarboxylic acid-based high-performance water reducing agent in the blank group prolongs the initial setting time, and the initial setting time can be further prolonged even when the polycarboxylic acid-based high-performance water reducing agent is added in the cases of examples 1 to 5. The experimental result proves that the polycarboxylic acid high-performance water reducing agent can be compounded with the retarder to realize a synergistic effect, so that the initial setting time is further prolonged.
Experiment for influence of polycarboxylic acid water reducing agent and different retarders on concrete chloride ion diffusion
2.1, experimental materials:
the blank group comprises the following components:
100 parts of water; 75 parts of cement; 70 parts of secondary fly ash; 500 parts of medium sand;
320 parts of crushed stone with the diameter of 8 mm; 500 parts of crushed stone with the diameter of 15 mm;
0.08 part of air entraining agent acrylic epoxy resin; 0.2 part of polycarboxylic acid water reducing agent.
Examples the components of each group were increased on a blank basis.
2.2, a detection method of chloride ion diffusion:
the method for measuring the permeability of the concrete to chloride ions mainly comprises several common methods such as an electric quantity method, an RCM method, an NEL method, a natural diffusion method and the like. The invention adopts NEL method to detect; referring to the NEL method of chloride ion diffusion coefficient method of Qinghua university, a concrete sample is processed and detected after a standard curing period of 28 days, and the concrete sample is made into a cylinder with the diameter of 100mm and the thickness of 50 mm. The diffusion coefficient test results are shown in table 2, where the unit of diffusion coefficient is: 10-12cm2And s. The unit of the compressive strength is MPa, and the compressive strength is the compressive strength of the mortar at the curing age of 7 d. The increment of the compressive strength is calculated by addingThe difference between the compressive strength of the example group after the admixture and that of the blank group.
2.3 the formulation of each component and the experimental results are shown in the following table 2:
table 2: experimental results of chloride ion diffusion
It can be seen from table 2 that different retarders and the same retarder have different mixing amounts, which affect the performance of the concrete, and the effects are not uniform, for example, the retarders with low mixing amounts, such as calcium saccharate, sodium carboxymethylcellulose and sodium tripolyphosphate, have lower diffusion coefficients and good permeation resistance; however, the calcium saccharate has no significant influence on the compressive strength of 7d, and the sodium carboxymethyl cellulose and the sodium tripolyphosphate have significant influence. Sodium gluconate, lignosulfonate and calcium saccharate have no obvious influence on the compressive strength of the curing age of 7d, and the diffusion coefficient is increased after the mixing amount of the lignosulfonate is increased, which indicates that the anti-permeability capability of the lignosulfonate is poor; the influence of the sodium gluconate and the calcium gluconate on the diffusion coefficient and the doping amount is small.
In the construction process, the dosage of the retarder is likely to change along with construction progress, construction conditions, construction requirements and the like, the change range is large, and the addition amount of the retarder is also related to the components of concrete. Therefore, in order to obtain a lower chloride ion diffusion coefficient, the concrete component of the invention preferably comprises the additives of the calcium saccharate, the sodium carboxymethyl cellulose and the sodium tripolyphosphate, but the improvement capability of the calcium saccharate on the compressive strength is limited, so the low-doped sodium carboxymethyl cellulose and the low-doped sodium tripolyphosphate can be preferably selected through the experiment.
In order to obtain a good diffusion coefficient in a reasonable mixing amount range of the retarder, namely the diffusion coefficient cannot be increased due to the increase of the mixing amount of the coagulant, sodium carboxymethylcellulose and sodium tripolyphosphate are required to be optimized as components of the retarder. According to the invention, by adding the quinoline carboxylic acid ethyl ester and the 5-hydroxymethyl furfural into the concrete, when high-doping amount of sodium carboxymethyl cellulose and sodium tripolyphosphate are used as retarders, the retarder still has good diffusion coefficient and good anti-permeability capability.
Influence of auxiliary agent on retarder sodium carboxymethyl cellulose and sodium tripolyphosphate
3.1, experimental materials:
the blank group comprises the following components:
100 parts of water; 75 parts of cement; 70 parts of secondary fly ash; 500 parts of medium sand;
320 parts of crushed stone with the diameter of 8 mm; 500 parts of crushed stone with the diameter of 15 mm;
0.08 part of air entraining agent acrylic epoxy resin; 0.2 part of polycarboxylic acid water reducing agent.
Examples the components of each group were increased on a blank basis.
3.2, a detection method of chloride ion diffusion:
the invention adopts NEL method to detect; referring to the NEL method of chloride ion diffusion coefficient method of Qinghua university, a concrete sample is processed and detected after a standard curing period of 28 days, and the concrete sample is made into a cylinder with the diameter of 100mm and the thickness of 50 mm. The diffusion coefficient test results are shown in table 3, where the unit of diffusion coefficient is: 10-12cm2/s。
Table 3: experimental results of chloride ion diffusion
In Table 3, compared with example 29 and example 30, example 29 is added with 0.06 part of quinoline carboxylic acid ethyl ester, example 30 is added with 0.05 part of 5-hydroxymethylfurfural, the diffusion coefficient of example 29 is obviously reduced compared with example 28, and example 30 has no significant difference with example 28, which shows that the addition of quinoline carboxylic acid ethyl ester can obtain better permeation resistance of example 29, and the diffusion coefficient is increased from 5.2 to 16.8 by the high-dosage sodium carboxymethyl cellulose as shown by component comparison; that is, when sodium carboxymethylcellulose is used as a retarder, quinoline carboxylic acid ethyl ester can reduce the diffusion coefficient of the concrete with high doping amount, and obtain lower diffusion coefficient, namely quinoline carboxylic acid ethyl ester inhibits the promotion effect of the sodium carboxymethylcellulose with high doping amount on the diffusion coefficient.
Similarly, the diffusion coefficient of the auxiliary agent 5-hydroxymethylfurfural added in the example 30 is not obviously different from that of the auxiliary agent in the example 28, and the inhibition effect of the 5-hydroxymethylfurfural on the sodium carboxymethylcellulose without quinoline carboxylic acid ethyl ester is shown. In contrast, as can be seen from the experimental components and comparative results of examples 32-34, the high loading of sodium tripolyphosphate also increases the diffusion coefficient from 3.9 to 11.6 compared to the low loading of sodium tripolyphosphate. Meanwhile, the comparison between the example 33 and the example 32 shows that the ethyl quinolinecarboxylate has no influence on the improvement of the diffusion coefficient by the high-content sodium tripolyphosphate, but the 5-hydroxymethylfurfural can inhibit the improvement of the diffusion coefficient by the high-content sodium tripolyphosphate.
Similarly, it can be seen in examples 36 to 38 that 5-hydroxymethylfurfural and ethyl quinolinecarboxylate do not have any inhibiting effect on the retarder lignosulfonate. Therefore, the 5-hydroxymethylfurfural and the ethyl quinolinecarboxylate have selectivity on the inhibition effect of the retarder.
Among the various types of pores that affect the diffusivity of chloride ions in concrete, the pores with a pore size of 5nm to 100nm, which have the most adverse effect, are fine capillary pores. Capillary condensation can occur in the pores, so that the hygroscopicity of the pores is enhanced; but also can generate larger capillary pressure and capillary hole permeability, so that the self-shrinkage of the concrete is increased, the surface layer permeability rate and the normal pressure permeability rate of the concrete are simultaneously accelerated, and the surface layer impermeability and the normal pressure impermeability of the concrete are comprehensively reduced. Factors affecting porosity, including water-cement ratio, raw material formulation, hydration level, curing method and admixture, have been reported in the literature. The retarder belongs to one of the additives and has certain influence on the porosity. It is experimentally found that an increase in the total pore volume will cause an increase in the diffusion coefficient, resulting in a decrease in permeation resistance. The porosity was measured by mercury porosimetry, methanol method, helium flow method, etc. and the porosity was measured by increasing the porosity of example 28 as compared with example 27 and increasing the porosity of example 32 as compared with example 31, thereby increasing the diffusion coefficient. Example 29 has a lower porosity than example 28 and example 33 has a lower diffusion coefficient than example 32; the two auxiliary agents can change the porosity of the concrete slurry under corresponding environments, and further change the diffusion coefficient.
The retarder can play a role in retarding, and because the retarder sodium tripolyphosphate can generate a stable complex with calcium ions, the formation of a hydration product Aft is hindered, the crystal growth of a hydration product CSH is inhibited, and the hydration of C3S and C3A is delayed at the initial stage of cement hydration. Similarly, the retarder carboxymethyl cellulose sodium molecule can form complex salt with Ca generated by cement hydration, the concentration of Ca ions in a liquid phase is controlled at the initial stage of cement hydration, the formation of a cement hydration phase is prevented, and the retarding effect is generated.
Claims (8)
1. A construction method of a dam in hydraulic and hydroelectric engineering is provided, wherein the rockfill dam comprises an upstream paving area, a panel layer, a cushion layer, a transition layer and a rockfill area; the construction method of the dam is characterized by comprising the following steps:
A. clearing dam shoulders and a foundation pit, excavating dam shoulder parts of two banks before closure according to the diversion flood-crossing requirement, and excavating a foundation pit part of a riverbed after closure; removing the covering layer of the dam abutment and the soft soil layer of the foundation pit, and removing accumulated water and impurities; moving earthwork obtained by cleaning, blasting and excavating to a slag yard to screen out stones;
B. arranging reinforcing steel bars in the foundation pit, and pouring concrete to form an upstream paving area; pouring rich-grout cemented gravel concrete in the foundation pit to form a base, and arranging an impermeable layer structure between the base and an upstream paving area for impermeable treatment;
C. pouring a rockfill area on the base, wherein the rockfill area is formed by repeatedly pouring and rolling multiple layers of roller compacted concrete; the method for pouring the roller compacted concrete comprises the following steps:
c1: firstly, pouring lower-layer roller compacted concrete and leveling, and pouring upper-layer roller compacted concrete before the initial setting of the lower-layer roller compacted concrete; the thickness of the lower layer of roller compacted concrete is 20 cm-25 cm, and the thickness of the upper layer of roller compacted concrete is 30 cm-35 cm; leveling after the upper layer of roller compacted concrete is poured, and rolling by using a vibration roller before initial setting until the surface is uniformly grouted; repeating the step C1 until the height of the rockfill area reaches the design height;
D. and sequentially filling a panel layer, a cushion layer and a transition layer from upstream to downstream on the rockfill area.
2. The construction method according to claim 1, wherein: the mortar-rich cemented sand gravel concrete comprises 100-150 parts of water, 100-150 parts of cement, 80-150 parts of fly ash, 800-1200 parts of sand and 1000-1500 parts of gravel, and the particle size of aggregate is 10-20 cm.
3. The construction method according to claim 1, wherein: the vibration pressure of the vibration roller is 300 KN-500 KN; the walking speed is 1 km/h-2 km/h.
4. The construction method according to claim 1, wherein: the strength of the slurry-rich cemented gravel concrete is C20-C25.
5. The construction method according to claim 1, wherein: the lower layer roller compacted concrete comprises
100 parts of water; 70-80 parts of cement; 60-80 parts of secondary fly ash;
400-500 parts of medium sand;
300 to 400 portions of crushed stone with the diameter of 5 to 10 mm;
400-500 parts of crushed stone with the diameter of 10-20 mm;
0.05 to 0.1 portion of air entraining agent; 0.05 to 0.5 portion of polycarboxylic acid water reducing agent;
0.05 to 0.5 portion of retarder sodium carboxymethyl cellulose or sodium tripolyphosphate;
0.05 to 0.1 portion of quinoline carboxylic acid ethyl ester; 0.05 part to 0.1 part of 5-hydroxymethyl furfural.
6. The construction method according to claim 1, wherein: the upper layer roller compacted concrete comprises
100 parts of water; 60-80 parts of cement; 60-80 parts of secondary fly ash;
400-500 parts of medium sand;
crushed stone with the diameter of 10 mm-20 mm: 300 to 400 portions;
crushed stone with the diameter of 20 mm-40 mm: 500-600 parts;
0.05 to 0.1 portion of air entraining agent; 0.05 to 0.5 portion of polycarboxylic acid water reducing agent;
0.05 to 0.5 portion of retarder sodium carboxymethyl cellulose or sodium tripolyphosphate;
0.05 to 0.1 portion of quinoline carboxylic acid ethyl ester; 0.05 part to 0.1 part of 5-hydroxymethyl furfural.
7. The construction method according to claim 5 or 6, wherein: the air entraining agent is acrylic epoxy resin.
8. The construction method according to claim 5 or 6, wherein: the lower roller compacted concrete comprises:
100 parts of water; 75 parts of cement; 70 parts of secondary fly ash; 500 parts of medium sand;
320 parts of crushed stone with the diameter of 8 mm; 500 parts of crushed stone with the diameter of 15 mm;
0.08 part of air entraining agent acrylic epoxy resin;
0.2 part of polycarboxylic acid water reducing agent; 0.4 part of retarder sodium carboxymethyl cellulose;
0.06 part of quinoline carboxylic acid ethyl ester; 0.05 part of 5-hydroxymethylfurfural;
the upper layer roller compacted concrete comprises:
100 parts of water; 75 parts of cement; 70 parts of secondary fly ash; 500 parts of medium sand;
340 parts of crushed stone with the diameter of 15 mm; 520 parts of crushed stone with the diameter of 32 mm;
0.08 part of air entraining agent acrylic epoxy resin;
0.2 part of polycarboxylic acid water reducing agent; 0.4 part of retarder sodium tripolyphosphate;
0.06 part of quinoline carboxylic acid ethyl ester; 0.05 part of 5-hydroxymethylfurfural.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910214907.0A CN110004884A (en) | 2019-03-20 | 2019-03-20 | The construction method of rock in a kind of hydraulic and hydroelectric engineering |
| CN2019102149070 | 2019-03-20 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN111206543A true CN111206543A (en) | 2020-05-29 |
Family
ID=67167519
Family Applications (2)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201910214907.0A Pending CN110004884A (en) | 2019-03-20 | 2019-03-20 | The construction method of rock in a kind of hydraulic and hydroelectric engineering |
| CN202010192824.9A Withdrawn CN111206543A (en) | 2019-03-20 | 2020-03-18 | Construction method of dam in hydraulic and hydroelectric engineering |
Family Applications Before (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201910214907.0A Pending CN110004884A (en) | 2019-03-20 | 2019-03-20 | The construction method of rock in a kind of hydraulic and hydroelectric engineering |
Country Status (1)
| Country | Link |
|---|---|
| CN (2) | CN110004884A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115403322A (en) * | 2022-10-08 | 2022-11-29 | 中国水利水电科学研究院 | Cemented earth-rock dam and construction method thereof |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110485377A (en) * | 2019-07-16 | 2019-11-22 | 中电建十一局工程有限公司 | A kind of light section canal lining construction method |
| CN114835443A (en) * | 2022-05-30 | 2022-08-02 | 中电建十一局工程有限公司 | Cemented sand gravel mixture and field mixing production process |
| CN115369823A (en) * | 2022-08-22 | 2022-11-22 | 中国水利水电第十一工程局有限公司 | Roller compacted concrete interlayer surface treatment method |
Family Cites Families (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103898877B (en) * | 2014-04-18 | 2016-01-20 | 清华大学 | Rock-fill concrete roller compaction construction method |
| CN105780737B (en) * | 2016-04-22 | 2017-10-17 | 长江水利委员会长江科学院 | A kind of super-high rockfill dam structure and its construction method for being applicable Hydraulic and Hydro-Power Engineering |
| KR101758023B1 (en) * | 2016-07-20 | 2017-07-13 | 한국수자원공사 | Concrete Mat And Geomembrane Sealing System Dam |
| CN205934862U (en) * | 2016-08-17 | 2017-02-08 | 中国电建集团西北勘测设计研究院有限公司 | Local high -modulus enrockment concrete -faced rockfill dam structure |
| CN106630792A (en) * | 2016-12-07 | 2017-05-10 | 广西金洪混凝土有限公司 | High-performance concrete |
| CN106638487B (en) * | 2017-01-19 | 2019-10-25 | 中国电力建设股份有限公司 | A kind of construction method combining checkdam and the combined dam |
| CN108457249B (en) * | 2018-01-29 | 2020-02-21 | 大连理工大学 | Structural design and construction method of composite panel gravel dam |
-
2019
- 2019-03-20 CN CN201910214907.0A patent/CN110004884A/en active Pending
-
2020
- 2020-03-18 CN CN202010192824.9A patent/CN111206543A/en not_active Withdrawn
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115403322A (en) * | 2022-10-08 | 2022-11-29 | 中国水利水电科学研究院 | Cemented earth-rock dam and construction method thereof |
| CN115403322B (en) * | 2022-10-08 | 2023-09-08 | 中国水利水电科学研究院 | Glue-fixed earth-rock dam and construction method thereof |
Also Published As
| Publication number | Publication date |
|---|---|
| CN110004884A (en) | 2019-07-12 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN111206543A (en) | Construction method of dam in hydraulic and hydroelectric engineering | |
| CN109763480B (en) | High-efficiency curing method for soft soil field with high water content | |
| CN101684038A (en) | Curing agent and construction method of weak soil | |
| CN104818707A (en) | Method for solidifying and curing dredger sludge and new dredger fill by applying cotton stalks | |
| CN108193648A (en) | Plasticity panel homogeneous dam | |
| CN110184872A (en) | A kind of seasonal frozen soil region road structure and its construction method | |
| CN105569071A (en) | Cement-based material underwater grouting or mud-jack rock block foundation construction method | |
| CN105000830A (en) | Double-expansion filling mortar | |
| CN103015399A (en) | Earthquake disaster reduction system for liquefiable foundation and foundation treatment method | |
| CN106087880B (en) | A kind of dam that 300 meter level is high and its construction technology | |
| CN205576857U (en) | Be suitable for hydraulic and hydroelectric engineering's super high enrockment dam structure | |
| CN102444116A (en) | Construction waste regenerated aggregate concrete pile and soil foundation treatment method thereof | |
| CN105951672A (en) | Construction technology for novel embankment and slope protection | |
| CN103774516B (en) | The underlayment stabilized treatment method of soft base cut subgrade | |
| CN105780737B (en) | A kind of super-high rockfill dam structure and its construction method for being applicable Hydraulic and Hydro-Power Engineering | |
| CN106702845B (en) | One kind preventing saline and alkaline permeable pavement structure | |
| CN102251499B (en) | Ecological permeability reducing method and ecological permeability reducing soil for river | |
| CN111908853A (en) | Self-compacting soil, preparation method thereof and construction method for backfilling municipal cavity | |
| CN105386448A (en) | Filling construction method for backward slope in rock-fill dam slope treatment | |
| CN108193649A (en) | Core-wall homogeneous dam | |
| Nguyen et al. | Application research of high pressure jet grouting pile in an underground engineering in Vietnam | |
| CN113914258A (en) | River revetment construction method and river revetment | |
| CN208701605U (en) | A kind of permeable breakwater based on cementingization enrockment | |
| CN108643132B (en) | Rolled concrete structure with composite slurry injected into stone slag material and construction method thereof | |
| CN202787295U (en) | Dispersive pile-permeable concrete pile novel dual compound foundation |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| WW01 | Invention patent application withdrawn after publication |
Application publication date: 20200529 |
|
| WW01 | Invention patent application withdrawn after publication |