When it is 5m from the pile top, the immersion vibrator shall be used for vibration.
Case 1 of construction method: the first step of anti slide pile construction at a construction site of renmuxin expressway: manually construct the lock mouth, drill with rotary drilling rig and take soil; the second step: cut the hole wall with a knife, and take soil with rotary drilling rig after the hole wall is cut by hammering method 00:0200:02 01:0001:00; the third step: prefabricate the reinforcement cage and hoist it for on-site installation; the fourth step: pour concrete 2 Case 2 of construction method: rectangular anchor pile construction in slope cutting protection project of front six elevation of Yunnan section of Yunnan Guangxi railway.
In order to prevent a small amount of soil falling off the shaft wall during concrete pouring, which may lead to pile breaking or interlayer, in order to ensure the concrete pouring quality, the mature process of underwater pile pouring of bridge pile foundation is adopted for the concrete pouring of anti slide pile, the dosage of the first batch of concrete and the buried depth of tremie are controlled, the concrete pouring is accelerated, the vibration on the top is strengthened, and over pouring is carried out, Prevent the surface from being too thick.
The fifth step is concrete pouring.
The third step is the fabrication and installation of reinforcement cage and the installation of acoustic measuring pipe.
Commercial concrete shall be used for concrete, concrete shall be transported by concrete mixer truck, and concrete shall be poured by concrete truck pump truck.
When vibrating the upper concrete, 5cm to 10cm of the lower concrete shall be inserted.
Step 4 inner diameter for conduit installation Ф 300, steel pipe with wall thickness of 4mm, standard length of each section is 2.65m, length of bottom section is 4m, and 1m and 1.5m auxiliary sections are provided.
When lifting the reinforcement cage, two lifting points shall be used.
Because square anti slide pile is better than circular anti slide pile in resisting thrust, the designed anti slide pile is mainly square pile.
Because there is no retaining wall, it is easy to collapse, so it is not suitable for hard rock stratum.
The disadvantage is that it has high requirements for the site.
The concrete shall be vibrated with a flexible shaft vibrator with a diameter of 5cm and a length of 12m.
When the last stiffening hoop approaches the orifice, place the steel pipe under the stiffening hoop, cross arm on the platform, and weld the lifting ring of the reinforcement cage.
The lifting ring is made of steel Φ 20 reinforcement, each reinforcement cage is symmetrically provided with 2 lifting rings.
The advantages are fast construction progress and guaranteed safety of construction personnel.
During vibration, follow the principle of fast insertion and slow extraction, and keep a distance of about 10cm from the reinforcement cage to prevent deformation of the reinforcement cage and falling off of the welding part.
When pouring concrete, the slump of concrete should be 18 ~ 22cm.
At present, there is no construction technology that can mechanically form square hole at one time.
After the reinforcement cage enters the orifice, it shall be righted and lowered slowly.
It is strictly prohibited to swing and collide with the hole wall.
A review and inspection system shall be established for the installation length of conduit to avoid pile breaking due to wrong installation.
The first step is to construct the lock mouth, and the second step is to excavate the pile body.
In order to ensure the quality of the tremie, a water tightness test shall be conducted for the tremie before pouring the pile foundation concrete to ensure the good condition of the tremie.
This paper introduces the construction process of square pile with two cases.
Because there is no wall protection during the hole forming process, in order to prevent the risk of hole collapse due to long-term exposure after hole wall excavation, the reinforcement cage must be uniformly fabricated nearby, and the reinforcement cage must be transported to the pile to be formed before hole forming.
During vibration, the vibrator shall be inserted into the concrete at an angle of 75 °, and the insertion and extraction speed of the vibrator shall be controlled.
(source: integrated on the Internet, the picture and copyright belong to the original author.
1.
XCMG 360 rotary drilling rig is used first Φ The pilot hole of 150mm round drill bit reaches half of the design depth, drill most of the soil, then use the inner side of the lock retaining wall as the guide wall, trim the hole wall with a self-made square cutter, then drill the round drill bit to the design depth, and then trim the hole wall with a square cutter; Cycle the above steps until it is corrected to the bottom of the hole, use a circular drill bit to move the drilling ballast soil out of the hole, and then transport it to the designated spoil area with a dump truck.
The concrete pouring frame is made of section steel, which is used to support the suspension conduit, hang the reinforcement cage, and place the concrete funnel on the upper part.
Construction method 3: refer to the following paper summary: This paper introduces three construction methods of mechanical excavation of square anti slide piles, all of which require rotary drilling rig to drill for soil first and then trim the edge.
In order to ensure construction safety and improve construction efficiency, mechanical excavation of anti slide piles is generally considered when large machinery can reach the anti slide pile construction site.
The reinforcement cage of the project is fabricated as a whole in the reinforcement processing yard, mechanically connected and installed by truck crane.
Thank China Railway Construction for providing relevant photos and instructions.
Until the concrete no longer sinks, no bubbles appear, and the surface is flat and bleeding.
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At the same time, accelerate the connection between processes and reduce the exposure of shaft wall.
Be careful when lowering the conduit to avoid hanging and touching the reinforcement cage.
First lift the reinforcement cage vertically, and then check whether there is bending deformation and correct it.
When pouring concrete with conduit, it can fall freely in the conduit, and the conduit is aligned with the center of pile.
In order to ensure that the reinforcement cage will not deform during hoisting and installation, a strong internal support shall be set for the reinforcement skeleton during processing to prevent the deformation of the reinforcement cage during transportation and positioning, and a platform shall be set.
