After the completion of hole forming, the debris and other garbage generated by the surrounding hole forming shall be cleaned in place immediately to ensure that there is no garbage within 50cm around the anchor hole.
After the initial grouting for 1-3 hours (the interval between the two grouting can be adjusted according to the actual situation), the secondary grouting shall be carried out according to the design requirements.
Wet operation method can complete the processes such as slag removal and hole cleaning at one time to prevent hole collapse without residual soil.
The annual variation range is generally 1.00 ~ 2.00m.
Grouting method: bolt grouting adopts secondary grouting method.
The following is understood through a group of on-site photos: foundation pit excavation, cushion pouring, measurement and setting out, mechanical drilling, hole forming form, hole cleaning, plugging After the completion of anti Ash Grouting, the pull-out reinforcement of the dowel bolt and the reinforcement of the pit bottom plate need to be connected.
After grouting, check whether the anchor bolt is centered.
At present, this method has been widely used in drilling construction in complex strata.
If the anchor grouting construction is not immediately after the anchor hole is formed, resulting in the inflow of sludge and sewage, the secondary hole cleaning shall be carried out before the anchor construction.
The rigid guiding function of the casing can also ensure the verticality of the drilling hole, and can effectively control the construction quality and the safety of the buildings in the state of Zhou.
The water level rises and falls with seasonal climate change, and the water level rises and falls with seasonal climate change.
A positioning frame shall be set on the anchor bar every 2m to ensure that the reinforcement can always be in the center of the hole.
The pipe following drilling technology is to follow the casing while drilling in broken rock to protect the hole wall.
The rivers in the territory mainly belong to XX water system, which has two sources, abundant rainfall, long sunshine time and short frost period.
The groundwater in the project site is very rich.
Geological conditions: it is known that the area where the project is located is dominated by mountains and hills.
Fixing Socket Angular End Nail Plate
Technical exhibition board [internal data, no external transmission] this chapter mainly uses the pit of steam turbine room workshop and raw material grinding workshop of a project in the south of our company to understand the process and operation matters of on-site construction.
The groundwater supply source in this area mainly comes from atmospheric precipitation and lateral supply in high-lying areas, and the discharge way is mainly evaporation and discharge to low-lying areas.
The process flow of construction is as follows: anchor rod fabrication – anchor rod positioning and setting out – drilling rig in place – correction drilling – hole cleaning – pressure grouting – lower anchor rod – secondary grouting – maintenance – uplift test acceptance.
2.
The position and angle of bending point are inconsistent with the design drawing Author: Hao Peng check: Cao Yong.
If there is deviation, straighten and fix it.
The reinforcement cannot be taken out when pulling out, otherwise the reinforcement shall be inserted and pulled out again.
Anchor support and installation: determine the blanking length of anchor bar according to the anchor length and design structure requirements, remove the rust and oil stain on the reinforcement surface, and weld and bend according to the design size and shape.
After grouting, the maintenance shall be carried out according to the specifications.
This construction method is widely used at home and abroad and can be applied to a variety of soft and hard layers.
The grouting pressure is 2.5-4.5mpa.
The problems prone to occur in this stage are: 1.
It is difficult to ensure the drilling quality and construction efficiency by using conventional construction technology.
Problems that are easy to occur in this process: the hole forming and slag removal of anti floating anchor rod is not timely.
When anchoring, it is necessary to ensure that the anchor bolt is centered.
The hole forming method of pit reinforcement binding: the hole forming method can be divided into dry operation method, wet operation method, dry wet combined operation method and pipe following operation method.
The geology of the pit of the project is moderately weathered shale.
3.
The length of grouting pipe is too short, which affects the grouting quality.
The setting of the positioning frame shall not hinder the free flow of slurry during grouting.
Wet operation method and pipe following operation method are commonly used.
The groundwater types are karst fissure water and upper stagnant water, and the water volume is large.
For the initial grouting, the grouting pipe shall be inserted into the hole 50cm away from the hole bottom, and the initial grouting pressure is 0.5-1.0mpa.
The groundwater is mainly rich in plain fill and karst fissures.
The annual average temperature is about 18 ℃, the annual average precipitation is 18xx mm, and the highest in history is 26xx mm.
The climate is mild and humid all year round, with the characteristics of subtropical monsoon climate.
Water resources are relatively abundant.
1% early strength agent and 6% expansion agent shall be mixed into the cement mortar.
The length of straight section of anchor rod blanking is not enough.
During the grouting process, the grouting pipe shall be pulled out while grouting, but the grouting pipe shall always be kept below the slurry surface until all the grouting pipes are pulled out.
When the secondary grouting reaches the predetermined pressure, the intubation shall be pulled out while grouting until the grouting pipe is pulled out.
The top and bottom of the anchor bolt orifice are coated with antirust paint 250mm respectively to protect the anchor bolt from corrosion.
The geological conditions of the site are complex and the groundwater level is high, which is easy to produce quicksand and collapse, and the strata that are not easy to form holes (such as pebble layer, medium coarse sand, loose broken sand, broken rock layer, high water bearing stratum, etc.) often encounter the problems of hole collapse and buried drilling.
According to the geological survey, the hardness of the rock is relatively hard, the rock mass is relatively complete, and the basic quality grade of the rock mass is grade III.
With the change of seasons and the advance and retreat of westerly belt, the four seasons change obviously.
During the survey, the measured groundwater is 0.00m ~ 5.00m.
considering the above geological and hydrological conditions, the pit in this area needs to take anti floating measures, and the foundation design grade is not grade A, so the anti floating bolt scheme is more suitable.
If the anchor bolt deviates during grouting, it is necessary to straighten it in time.
