Mortar masonry; Stone dam; Architecture; quality management
I. Overview of the Project
The project contents include earth and stone works of regulating tank, bottom seepage prevention, floating roof system, gas collection system, heavy objects on film and rainwater collection system, peripheral anchorage and stability, etc. The mortar masonry dam in this project is a M 10 mortar masonry gravity dam, with the crest elevation of 3265438+307m (the elevation adopts the national elevation datum 1985), the upstream dam slope of the rockfill dam is 1:0. 1, and the downstream dam slope of the rockfill dam is/kloc.
Second, the construction preparation
1. cement ordinary silicate 32.5R cement must have a factory certificate and a factory quality acceptance certificate before it can be accepted and put into storage. After cement enters the site, it must be inspected by the national quality inspection organization, and its variety strength and performance must meet the design requirements.
2. Mortar adopts M 10 (masonry) and 1:2 cement mortar (jointing plastering), which is mechanically stirred. Mortar has good workability, water retention and water permeability, and the consistency is generally 4-6 cm; Mortar is made of natural sand, which is hard, clean and well graded. The maximum particle size is less than 5 mm, and the average material diameter is not less than 0.25 mm. The silt content of sand shall not exceed 5%.
3. The block stone used in block stone masonry is hard, dense, free from weathering, cracks, adhesion and cleanliness, and its strength meets the design requirements (MU20).
4. The main machines are excavators, dump trucks, mortar mixers, hopper cars, shovels, grey knives, plain films, wire pendants, small white wires, tape measures, spirit levels, measuring rods, small buckets and grey troughs.
Third, the construction technology
1. Measuring unreeling uses NTS-320 Southern Total Station to measure the relevant dimensions of the four main angular axes of the unreeling rockfill dam. According to the results of measuring and setting out, positioning piles are set, and the design axis is measured by the external control axis. Re-survey the original landform of the excavation site with S3 level, and make records. Spread out the excavation line with lime to carry out foundation excavation.
2. Earthwork excavation Earthwork excavation is carried out with the cooperation of excavators and dump trucks, and soil is taken from side to side and from top to bottom in layers. When the excavation is close to the top surface of subgrade design, pay attention to reserve the rolling settlement height according to the soil conditions to prevent over-excavation. In the process of excavation, the basement working face should keep a certain vertical and horizontal slope as designed.
3. Masonry structure
(1) Basic processing. The bearing layer of the foundation of the masonry dam in this project is ③-2 strongly weathered hanging stone, and the depth of the foundation entering the bearing layer is not less than 0.5m After the foundation is excavated to the design elevation, it must be checked and accepted by the design, survey, supervision and owner before entering the next working procedure.
(2) Process flow. Mortar block stone should be laid out according to the center line of foundation, and the hanging line should be laid in layers, each layer is about 300 ~ 400 mm high. Masonry method adopts slurry sitting method. With larger rubble, build by laying bricks or stones corner, junction, and then to the middle masonry. Before bricklaying or masonry, the stones should be placed in a place that matches the size, with the big face down, the exposed face flush, and the oblique mouth inward, and the mortar should be laid one by one to make the mortar full. Large gaps between stones should be blocked with mortar first, and then embedded with gravel. It is forbidden to fill pebbles before grouting. Generally, the width of mortar joint is about 20 ~ 30 mm, and the thickness of mortar is 40 ~ 50 mm When building, the upper and lower skins of stone materials should be staggered, and the inside and outside should be staggered to avoid heavy joints, dry joints, empty joints and holes. At the same time, attention should be paid to placing stones to avoid dislocation, splitting and bulging of masonry after bearing. For example, paving rubble has different shapes and sizes, and it is difficult to lay it flat on each layer of skin. You can also take the method of laying bricks without dividing skin, and generally tile them at a certain height. At the corner and junction, large and regular crib stones should be used to build each other and at the same time. If necessary, steel bars should be set. At room temperature, the daily masonry height of the block stone shall not exceed 1.2m, and the masonry can be continued after stopping for 4h. Every 3 ~ 4 layers of masonry should be roughly leveled once. When the work stops halfway, the cracks in the stones should be filled with mortar, but when the masonry continues, the upper surface of this layer should be covered with mortar. When laying bricks to the design height, flat large stones should be used for coping and fully leveled with cement mortar. The masonry method of block stone is basically the same as that of concrete block, and the masonry forms include transition, Ding Shun stacking and Ding Shun assembling. The first and top floors of each floor were built by Tintin. Before laying, the number of layers should be calculated according to the average thickness of stone and mortar joint, and the number of stay wires should be set. When laying, the upper and lower skins should be staggered and overlapped; At the corner of masonry, stones should overlap each other. "Slurry spreading method" is used to spread slurry, the thickness is 20 ~ 30 mm, the vertical joints are filled with mortar, and compacted until it overflows. The thickness of mortar joint is10 ~ 20 mm.
(3) jointing. The jointing of stone walls should keep the natural joints of masonry, generally using flat joints or convex joints. Tick off the joint before jointing, scrape the mortar to a depth of 20 ~ 30 mm, wet the wall with water, and then tick off the joint with 1: 2 cement mortar. Joints shall be uniform and consistent in depth, and the crossing and T-joint shall be smooth. Tickle joint should be carried out after 24 hours of mortar masonry construction, and the joint width should not be less than the joint width, and the joint depth should not be less than 2 times of the joint width. Before jointing, the joint must be rinsed clean, without residue of ash and water, and the joint surface should be kept moist. Jointing mortar must be mixed separately, and it is forbidden to mix with masonry mortar. When jointing is completed and mortar is initially set, the surface of masonry shall be scrubbed clean and covered with soaked materials for at least 21d. During the curing period, water should be sprayed frequently to keep the masonry moist to avoid collision and vibration.
(4) Masonry maintenance. The exposed surface of masonry should be maintained in time between 12 ~ 18h. The exposed surface should always be kept moist and covered with sacks or straw bags, and the surface should always be watered and maintained. Generally, the curing time is not less than 14d. In winter, instead of spraying water, we use sacks to keep warm. Before the masonry does not reach the required strength, it is not allowed to pile up heavy objects or chisel stones on them at will to avoid vibration damage to the masonry.
Fourth, quality standards.
1. The quality and specifications of the main control engineering stone must meet the design requirements and construction specifications. The variety and strength of mortar must meet the design requirements. Corners must be laid at the same time. If the junction cannot be laid at the same time, it must be inclined.
2. Masonry groups should generally be built inside and outside, with staggered joints up and down, and the positions of pulling stones and masonry are staggered and evenly distributed; The hair is divided into skin and spread horizontally, without filling method; Pull stones every 0.7m2 metope not less than one piece; The stone is placed smoothly, and the thickness of mortar joint conforms to the provisions of construction specifications. The stone wall is closely jointed, firmly bonded, clean, neat, clear and beautiful.
Five, the construction matters needing attention
The stone used must be kept clean, and the heavily polluted or rusty stone should be cleaned to ensure the bonding strength of masonry. Masonry mortar should be measured strictly according to the material to ensure the accurate mixture ratio; Mortar should be mixed evenly and the consistency meets the requirements. Masonry should be leveled to make the straight light consistent. Masonry should be leveled on both sides, and the axis and sideline should be regularly checked to ensure straightness, correct axis and no displacement. Stone masonry should pay attention to the choice of stone materials, so that the size of stone materials can be used together, and the size of stone materials can not be too small, so as to ensure the mutual pressure and Rachel between stone materials and avoid the phenomenon of bulging and double skin inside and outside.
Conclusion of intransitive verbs
To sum up, the quality control of masonry dam project is ideal, which has an important impact on its function and service life. In the process of construction, we must strengthen quality control and do a good job of supervision and testing. In view of the author's limited level, it is necessary to continue to study and summarize in the future work and do my part for the development and progress of the project.
refer to
[1] Wu Guiyao, Huang Zongying, Jiang Jianlin. Construction technology of high concrete face rockfill dam [J]. Water Resources and Hydropower Technology, 2006(07).
Zhang Ping. Research on construction simulation and schedule control of high core rockfill dam based on real-time monitoring [D]. Tianjin University, 20 1 1.
Dai Yanqin, Ding Lei, Wei. Study on Gravel Soil Filling Control Technology of Earth-rock Dam [J]. Science and Technology and Enterprise, 20 12(08).
Zhong, Hu Chengshun,. Computer integrated simulation of high earth-rock dam construction [J]. Journal of Tianjin University, 2004( 10).
Jiang haibo Study on mechanical characteristics and permeability coefficient of geomembrane seepage control in earth-rock dam, dam foundation and reservoir area [D]. Xinjiang Agricultural University, 20 1 1.