(4) Coring requirements: three rows of boreholes are designed.
Abstract: in the interregional tunnel of metro construction of Dongguan rail transit line R2, the tunnel excavation needs to pass through the granite stratum section with rich water, high pressure, upper soft and lower hard and boulder.
Straight hole grouting hole is arranged between the subgrade slope and the two lines.
Therefore, in the current construction projects, it is important to It is very necessary to strengthen the foundation.
In order to ensure the drilling quality, at least one borehole in each row is required to be coring when it is expected to enter the top interface of Cambrian limestone.
2) 6 Effect Analysis: the geophysical prospecting and drilling verification of the abnormal area of 21121 working face before and after grouting show that the abnormal low resistance area of the working face has been transformed into a high resistance area.
Whether the foundation construction technology is scientific and reasonable is directly related to the quality of the whole building structure and the exertion of the construction function, and it also determines the construction cost, project cost and the safety of constructors.
The grouting reinforcement technology of forward grouting and cement water glass double slurry is adopted to improve and optimize the traditional mountain method construction technology, and successfully passes through the complex stratum with rich water, It ensures the safety of tunnel construction, better controls the land settlement, and provides a good amount of experience and methods for underground tunnel construction in water rich, upper soft and lower hard weathered granite land area.
5 construction process (Fig.
It is verified that there is only a small amount of water output from the drilling hole, and the water output gradually decreases to zero within 3 days, and the floor integrity and water impermeability are enhanced.
3 grouting steps (1) Hole arrangement.
For local or overall deviation of house structure and engineering structure caused by various reasons (such as foundation settlement and foundation construction), stress removal method, pile cutting method, jacking method and other technologies shall be adopted, The information feedback method is used to correct the deviation.
2.2.
10 sections are randomly selected for core pulling inspection.
2.
(2) Grouting.
If all the slurry enters the core sample and the thickness is about 10mm, it indicates that the base course has been filled and meets the strength requirements.
The core drilling test of random sampling shows that the compactness and strength of the concrete structure after grouting meet the requirements.
Key words: water rich stratum, grouting reinforcement, double liquid slurry, grouting volume, grouting pressure 1 preface with the rapid development of China’s economy and the acceleration of urbanization, subway construction has been carried out in major cities across the country.
The drilling process shall be carried out in strict accordance with the set hole diameter, angle and direction.
According to different locations, the ground quality encountered during subway construction is also different, especially the granite stratum sections with water rich, high pressure, upper soft and lower hard are rare, Water gushing, sand gushing and other disasters are often encountered, which brings great difficulties and potential safety hazards to the construction.
After the holes are drilled, water is injected into the holes with a grouting machine to check whether the pipes are blocked.
[Key words] foundation; building foundation; replacement method; the construction technology and reinforcement technology of foundation reinforcement not only affect the project quality, but also related to the project cost.
Click the blue word above to pay attention and send you a high-quality material for free Oh, key points of grouting construction technology for foundation subsidence of Chaohu Lake deep crack grouting reinforcement technology, and the length of orifice pipe shall not be less than 16m; For boreholes with a depression angle of less than 20 ° or an included angle of less than 10 ° with the roadway, the running length of orifice pipe shall not be less than 20m.
The internal deep cracks in the structure are reinforced by grouting and seepage water to stop leakage, so as to restore the overall structure It is also a mature technology that has been applied to mass concrete structures such as dams and high-rise building floors for many times.
Deviation correction of house structure and foundation and foundation reinforcement technology.
Prepare and treat the construction site before grouting to ensure that the site is flat; Prepare grouting and drilling equipment, formulate drilling construction scheme, prepare grouting fluid, check the operation of grouting pump, mixer and other equipment, check the connection and sealing quality of pipelines and joints, and dig sump and groove along the drilling position; Test the pump and check whether the water absorption of the equipment is normal.
Key points of grouting construction technology for foundation subsidence of Chaohu Lake [Abstract] this paper mainly expounds the foundation reinforcement technology and reinforcement methods of construction engineering.
The grouting material adopts p? 042.5# cement with slurry concentration of 1.1 ~ 1.2t/m3, and the slurry concentration is the principle of thin thick thin during grouting; When the grouting pressure is close to the design final pressure, the grouting pump is adjusted from high gear to low gear, and the slurry concentration becomes thinner gradually.
2.5 grouting effect evaluation due to the huge vibration caused by train operation, the railway subgrade has obvious subsidence before grouting, and there are cracks on both sides of the frame, which poses a serious threat to the safe and normal operation of the train.
The construction scheme must be combined with the project quality, geological conditions, engineering structural characteristics, construction period and meteorological conditions to optimize the construction scheme, design reasonable construction process and ensure the project quality The foundation construction of building engineering belongs to the foundation construction link of housing construction project, and it is the most critical construction process at the same time.
4.7 slurry ratio.
At present, the deep cracks in the grouting treatment have reached 2m.
2.2.
According to the method of first foundation pit slope and then subgrade slope, the slurry concentration shall be increased from thin to thick.
If there is any error, the slope of other boreholes shall be adjusted in time.
3 construction precautions (1) during construction, construction personnel shall pay attention to safety and shall not touch the net pole and railway; before construction, fence shall be set outside the grouting range to avoid falling of personnel and articles, causing danger and affecting the progress of construction..
Building foundation plays an important role in supporting high-rise buildings.
Detailed records shall be made to record the start and end depth, drilling depth, drilling tool size and rock cracks Condition, rock name and final hole depth, etc.
After grouting reinforcement, the slurry solidifies and fully fills the cracks, improves the bearing capacity of subgrade soil, effectively avoids the occurrence of collapse and ensures the safe driving of the railway.
According to the actual situation, rectangular holes are arranged with row spacing of 23cm and column spacing of 18cm, and uniformly numbered.
