1. Vertical well construction and excavation work (1) General construction method of well back plate The circle spacing of the well ring is generally 1.0m. When encountering a soft section, first dig the section to retain the annular step, and then dig up the full section, and then erect the temporary support of the back of the well, the circle is generally about 0.5m, the maximum is less than 1.0m. Masonry wall demolition operations generally use a metal template type, the use of material handling concrete pipes, pouring concrete wall integrally. (2) General construction method for hanging the wall For stable topsoil, full-section excavation is used. When excavating the earth, the center of the wellbore is dug first, then the Zhoubang is excavated. After the excavation is completed, the trays are laid, the steel bars are hung, the metal formwork is erected, the measurement is corrected and the mold is stabilized, the concrete is poured, and finally the installation is completed. The joints are well connected to the well wall. For the unstable topsoil, the semi-circular section is used for excavation and wall-laying, and then the other semi-circle is dug. The vertical joints of the concrete are to be beveled, and the quilting is staggered up and down. The wall of the hanging well is carried out from top to bottom. It is required that there should be a wall seat or a concrete lock at the upper part of the well wall, and the hooks for rooting of the hanging well wall should be reserved; the joint of the well wall should be tight and the concrete filling should be compact; (3) Sheet pile construction method The construction of the sheet pile needs to be completed before the wellbore is excavated. It can be directly driven into the ground on the ground, forming a protective ring around the wellbore, or it can be driven downhole as a leading support structure for wellbore excavation. Pile construction method Topsoil construction should pay attention to, if there is sand and mud, the sheet pile must be immediately replenished and filled with straw bag to filter the sand; if the working face is muddy, the insertion depth of the sheet pile must be increased. . The construction of the sheet pile method should be combined with the advancement of the small well to reduce the water level. Second, the vertical surface construction work improvement work The topsoil construction lifting method can be upgraded by a simple lifting method and a lifting system consisting of a standard derrick. Simple lifting methods include tripods, simple gantry, tent derricks and truck cranes. 1, tripod The height of the tripod is determined according to the lifting requirements, generally not less than 6m. With a bucket of about 1 m 3 , the lifting height should generally not exceed 20 m (small wells can be slightly deeper). 2, simple gantry It can be used for topsoil construction with a depth of no more than 40m. 3. Tabernacle derrick The basic structure is a four-column type and can be applied to topsoil construction with a depth of about 80 to 100 m. 4, truck crane The small bucket with 0.5~1m 3 is suitable for wellbore construction with a depth of not more than 30m. Third, vertical well topsoil construction precipitation work 1. Working face lowering water level method In the unstable soil layer, the working face advanced well or advanced drilling is often used to reduce the water level. 2. Well outside drainage hole reduction water level method The method is to drill holes around the predetermined wellbore, and penetrate the impervious layer, then pump the water in the hole to form a precipitation funnel, so that the water level of the working surface is lowered, and the working face of the wellbore is kept under waterless conditions. Preservative Agent,Sodium Benzoate,Benzoic Acid,Sodium Bicarbonate Tianjin Centerstar Chemical Co., LTD. , https://www.centerstarchem.com