According to the design requirements, code for construction and acceptance of water supply and drainage structures and the operation manual prepared by the technical team of the project department, the supervision implementation rules for water flushing open caisson construction and Disclosure materials for construction supervision of water flushing open caisson.
② Wash the soil layer by layer, control the thickness of each layer within 300mm, and control each layer within 100mm in the final settlement stage, and strictly control the flushing and soil borrowing speed..
(4) According to the relevant provisions in table 7.4.5-2 of code for construction and acceptance of water supply and drainage structures (gb50141-2008), when the total sinking depth is less than 10m, the allowable deviation of the center position of the blade foot plane shall not be less than 100mm after sinking in place.
As the key construction project of “five water co governance” in Zhejiang Province and the livelihood project of Huzhou City to promote “urban water supply integration”, Huzhou new Taihu water plant project is located in Nanxun District, Huzhou City, Zhejiang Province, with a total investment of 123 million yuan.
(6) After the “three major causes” of deflection of open caisson are determined, the supervision department shall timely require the construction project department to determine the major cause countermeasures, set objectives and formulate measures according to the determined “three major causes”, and track and supervise the implementation process, as shown in Table 1.
With the accelerating process of urbanization and the continuous expansion of urban scale, as an important part of public and municipal infrastructure, the demand for urban water supply will be increasing and growing.
For soil flushing, the high-pressure water pump shall be used to shoot the high-pressure water flow (pressure ≥ 8kg) through the high-pressure water gun, and the soil in the well (around the blade foot) shall be washed in layers to form flowing mud, which shall be collected into the slurry pit, and then the mud shall be sucked out by the strong mud suction pump, The sludge is discharged to the mud sedimentation tank outside the well through the sludge discharge pipe, and the self weight of the reinforced concrete open caisson is used to sink naturally and evenly.
(2) The supervision department reviewed the quality and safety technical operation manual of water flushing open caisson construction prepared and submitted by the technical team of the project department.
Urban water supply safety is the lifeline of urban production and life.
This paper focuses on the construction supervision of open caisson in the construction project of water plant Introduction to the author Shen Haiming: male, born in October 1970, bachelor degree; National registered supervision engineer; Deputy general manager of Zhejiang Yongcheng Construction Engineering Management Co., Ltd.
Through organizing professional training and assessment, relevant construction personnel mastered the construction technology of water flushing open caisson.
In process control of water flushing open caisson sinking construction (1) Before the construction of water flushing open caisson, the technical team of the project department carefully prepared the operation manual of water flushing open caisson construction quality and safety technology, and explained, trained and assessed all construction personnel participating in the construction.
There are two structures in total.
Abstract: in the water plant construction project, the open caisson construction method is adopted for the reinforced concrete suction well.
2).
It is cast on site with C30 reinforced concrete (impermeability grade P6).
If the conventional drainage and soil excavation sinking method is adopted for construction, it is very easy to cause the phenomenon of inclination of the open caisson during the sinking process, and the engineering construction quality is difficult to be guaranteed.
It is designed according to the standard of 400000 tons / day of water supply capacity.
(5) In view of the main key problems of the deflection of the open caisson, the supervision department carefully carried out the causal analysis, and confirmed from the causal analysis diagram (Figure 1) that the lack of professional operation skills of operators, the uneven sequence of soil erosion in the well and the insufficient construction monitoring frequency are the “three main reasons”.
2.
Therefore, the technical team of the construction project department has prepared two special construction schemes of “drainage excavation open caisson sinking method” and “water flushing open caisson sinking method”, invited relevant expert groups to demonstrate the two special construction schemes, and finally determined that the water flushing open caisson sinking method is the construction scheme of the project.
(4) Based on the factors of geology, quality, safety and construction period objectives, the supervision department timely worked with the technical team of the construction project department to investigate the common quality problems in the past open caisson construction.
When the open caisson sinking process of water flushing method is used, the supervision department communicates with peers on the quality, progress, investment, safe and civilized (green) construction control measures and achievements in the implementation process.
The disclosure was made to the technical team of the project department and the construction personnel of the project department in the form of regular meeting of supervision special disclosure, further expounded the technical points and difficulties in the construction of water flushing open caisson, and did a good job in advance control.
(3) Before the construction of water flushing method, the flushing equipment shall be hoisted into the well and installed in place.
Key words: water plant construction open caisson construction front word Water is the source of life, the essence of production and the basis of ecology.
1 ~ 6, which scours symmetrically from the middle to the four sides (Fig.
Advance control of sinking construction of open caisson by water flushing method (1) Construction process of water flushing open caisson sinking process: installation and laying of water transmission and sludge discharge pipeline → installation of high-pressure water pump (gun) and sludge discharge equipment → high-pressure water flushing and sludge sinking → monitoring of structure plane and elevation data → correction of deviation according to monitoring data → sinking in place and sealing the bottom.
(2) The plane elevation of the construction site is 2.150m (yellow mark), the elevation of the bottom of the suction well blade is -6.500m (yellow mark), the elevation of the bottom plate is -4.300m (yellow mark), the elevation of the top plate is 4.200m (yellow mark), and the sinking depth of the open caisson is about 8.5m.
It was found that 70% of the open caisson deviated, 12% of the open caisson over sank, 8% of the open caisson horizontal displacement and 5% of the open caisson sudden sank in case of silt, The proportion of being blocked by unidentified obstacles is 3%, and the proportion of other (environmental and weather factors) is 2%.
is mainly engaged in construction project supervision, engineering management, technical management and whole process consulting.
The average score of the assessors reached 93.5 points.
The construction project has won the “Qianjiang Cup” high-quality project in Zhejiang Province and the “standard chemical site for safe and civilized construction in Zhejiang Province”.
The project supervision department and the technical team of the construction project department shall control the deviation within 60mm.
3.
1 design requirements, structure and site conditions of reinforced concrete suction well (1) The plane size of the suction well is 10.7 × It is 8.2m and the total height of the structure is 10.7m.
At the same time, it is equipped with a strong mud suction pump with pipe diameter of 159mm and power of 50KW to be responsible for mud discharge.
It is not difficult to see from the above data that the deflection of open caisson is the main quality problem in open caisson construction.
(3) According to the soil layer distribution provided in the geological survey report, there is about 2.3m thick silty sand layer in the geological profile layer of the sinking area of the open caisson, and the geological conditions are complex.
Through the joint efforts of all participants, the construction project has successfully completed various construction objectives, completed on schedule and put into normal water supply.
The water treatment process of the water plant: ozone oxidation pretreatment + coagulation sedimentation conventional treatment + ozone and activated carbon advanced treatment process.
(2) Equipment composition of water flushing construction process: the project adopts a set of flushing facilities in the well composed of two high-pressure water pumps with pipe diameter of 135mm and power of 15kw and high-pressure water guns.
The water supply capacity of phase I project is 200000 tons / day, which is composed of 16 unit projects, The total area of the plant area is about 190 mu.
(3) Layered and balanced soil erosion: ① Scour the soil according to the sequence of impact layout, and the sequence of soil flushing is shown in Fig.
It is closely related to social development and people’s production and life.
The following is an analysis of the key points of open caisson construction supervision in the construction (supervision) of the new Taihu water plant in Huzhou City.
