Development trend of rubber dam
Judging from the development trend of rubber dams, it can be said that the situation is good. There are three main reasons. First, the rubber dam's manufacturing and construction and installation technology is relatively mature. Second, the rubber dam has a wide adaptability and the third is the smooth exchange of technical information. These three conditions are critical to the development of rubber dams.
1 dam bag manufacturing and construction and installation technology
The manufacturing technology of rubber dams is mainly embodied in the manufacturing and processing of rubber dam bags and anchoring systems. The tensile strength of nylon silk canvas woven by our country before the 1990s is generally below 300KN/m, and the number of canvas layers of a 6.0m high rubber dam bag is 5 layers, which is very difficult to manufacture in dam bags. of. In 1999, the canvas with a tensile strength of 500KN/m was successfully developed in China, so that the canvas layer of the 6.0m high rubber dam bag became 3 layers, which is completely achievable in the manufacture of dam bags. In 2002, the steel wire reinforced rubber dam was successfully developed in China. The tensile strength of a single steel wire is 6 times that of nylon yarn. In this way, the construction of a 6m high rubber dam can meet the design strength requirements with a two-layer steel mesh, making the hope of building a higher rubber dam in the future a reality.
At the same time, the processing technology of rubber dam bags has also been greatly developed. In the past, rubber dams were mostly produced in sheet production, and the site was lapped on site. The latitudinal tensile strength and other quality problems after lap joints were also difficult to control, which brought many difficulties to construction, installation and operation management. In particular, the rubber dam is subjected to latitudinal tension at the side (shore) slope. When the slope of the slope is steep and the anchor line design is not reasonable, the latitudinal tension of the dam bag sometimes reaches 100% to 120% of the tensile force. It may cause tearing of the dam bag. In 1998, the country successfully developed a jointless rubber dam bag. The processing technology of the lapless rubber dam bag is formed on the large squeezing press, and the canvas is directly misaligned and lapped, and the stress conditions are good, which avoids the damage of the dam bag when it is lapped and used at the construction site.
In addition to the dam bag manufacturing and processing technology, the anchoring system of the rubber dam is also a key issue in the construction of the rubber dam. Whether the agglomeration is single-line anchoring or double-wire anchoring, from the perspective of the anchoring structure of the current rubber dam, it can be roughly divided into three types: bolting plate anchoring, wedge extrusion anchoring and capsule water-filling anchoring. These three anchor types are relatively safe and mature in design calculation, installation and management. At present, the main problem of the anchoring system of the rubber dam is how to arrange the anchoring groove (line), which is more conducive to the force of the dam bag and the flatness and beauty of the dam shape. At present, the improved anchor groove arrangement is adopted in the country, that is, the upstream and downstream anchoring grooves are arranged by oblique lines. This arrangement improves the stress of the dam bag, and the dam bag is relatively flat and beautiful. However, some problems with the anchor groove (line) arrangement and the dam plug are still worthy of further study. The construction and installation of the rubber dam shall be carried out in strict accordance with the requirements of the Technical Specification for Rubber Dams SL227-98 of the Ministry of Water Resources for construction, installation, inspection and acceptance.
2 adaptable and widely used
As a low-head water-construction building, rubber dam is simple in structure, flexible in operation and simple in operation. It is used to inflate and block water during use. It can be over-flowed during flood discharge, does not block water, and does not hinder flooding. It can be built in irrigation channels. It can be built on the Dajiang River; it can be built in mountain rivers or in urban plains; it also has certain adaptability to rivers with poor geological conditions and high sediment content. Therefore, it can be said that the rubber dam is a low-head water retaining structure, and the adaptability is very strong. At the same time, the construction cost of rubber dams is also very low. According to the domestic statistical analysis of some existing construction materials, a considerable scale water storage project is constructed. The rubber dam scheme is adopted, generally 30~75% of steel can be used less, and less wood is used. 60%, less cement 20~80%, less investment 20~60%.
The rubber dam is based on its strong adaptability, convenient construction and low cost, and its use range is relatively wide. For example, the Weihe Park in Taiyuan City, Shanxi Province, built four rubber dams in the 6km long river section of the urban Weihe section, forming a three-level water storage lake covering an area of 300hm 2 . Four theme plazas, six natural scenic spots and seven sightseeing spots have been arranged on the green platforms on both sides of the river. It has become the largest and most concentrated public green playground in Taiyuan. For example, in the comprehensive management project of the Xianyang City section of the Weihe River in Shaanxi, five rubber dams were arranged in the main stream of the Weihe River. Among them, there are 3 rubber dams in the water storage channel, the dam height is 3.0m and the dam length is 300m. The dam is equipped with two rubber dams with a dam height of 3.0m and 4.8m and a dam length of 200m. The total water storage capacity is about 6.73 million m 3 . It is necessary to fully develop and utilize water resources, improve the urban landscape along the river in Xianyang City, improve the investment environment in Xianyang City, and create a living environment in which people and nature coordinate with each other. According to the survey, some areas of rubber dams are currently under construction or have been built. The construction of these rubber dams is mainly used to improve the urban natural environment, urban water supply, and agricultural irrigation. Therefore, some small and medium-sized water storage projects use rubber dams as the preferred dam type.
3 technical information exchange
The development and promotion of rubber dams mainly rely on technical information exchange. The Ministry of Water Resources held 85 scientific research, design, production and management units in Benxi City, Liaoning Province, which participated in the “National Rubber Dam Bag Forming and Experience Exchange Meeting” with 112 personnel. The meeting summarized and exchanged experiences on the promotion and promotion of rubber dams in China for more than ten years, and published and published the "Selection of Technical Data for Rubber Dams", which has made significant contributions to the technical development and promotion of rubber dams in China. The Ministry of Water Resources approved the issuance of the "Technical Specification for Rubber Dams" SK227-98 to make the engineering design institute of the rubber dam, construction and installation, and economically reasonable. The technical information exchange of rubber dams is an extremely important task in the development and promotion of rubber dams.
What are the main manufacturers of rubber dams?