4.2 percussion drill percussion drill is a kind of drilling rig.
Viscometer 1-funnel, 2-tube, 3-measuring cup 200ml, 4-measuring cup 500ml, 5-Screen and cup ③ sand content (%): measured by sand content meter on site (Fig.
The scope of application is applicable to the construction of pier pile foundation of various soil layers, sandy soil, crushed (Pebble) soil or bedrock below medium hardness of highway bridges.
When the groundwater level is high or its flow velocity is large, the index takes the high limit, otherwise the low limit; 2.
For the drill with high torque power head and automatic internal locking telescopic drill pipe, it can adapt to the construction of slightly weathered rock stratum.
(4) the survey team shall survey and set out the pile position, accurately set out the pile position center with the total station according to the baseline control network and pier design coordinates, and fix the position with cross piles; Measure the ground elevation with a level to determine the drilling depth, and the measurement error shall be controlled within 5mm.
(6) The connection of the casing shall be free of protrusions, and shall be resistant to tension and pressure without water leakage.
(4) The height of pile casing should be 0.3m above the ground or 1.0 ~ 2.0m above the water surface.
With different drilling tools, it is suitable for hole forming operation of short spiral, rotary bucket and rock stratum.
When there is confined water in the borehole, it shall be more than 2.0m higher than the stabilized confined water level.
(6) organize mobilization and inspection of steel, cement, gravel and other materials, and obtain various raw materials and their sampling test reports, concrete mix proportion design reports and relevant data.
According to the construction organization design, reasonably arrange the location of mud pit and sedimentation tank.
7-2)..
The riverbed with scouring effect shall be sunk no less than 1.0 ~ 1.5m below the local scouring line.
At the same time, the geological checklist shall be prepared, the field verification shall be carried out according to the drilling conditions during the construction process, and the verification data shall be filled in.
(3) level the site, remove sundries, replace soft soil and compact it.
It is mainly used for drilling in hard geological strata with rocks.
The time required to fill the 500ml measuring cup (s) is the viscosity of the measured mud.
The working platform must be firm and stable, and can bear all static and live loads during construction.
After acceptance, protective measures shall be taken to prevent pile position change.
Equipped with suitable transformer or diesel engine.
Measure 200ml and 500ml mud respectively with open measuring cups at both ends, filter out large sand particles through the filter screen, inject 700ml mud into the funnel, and then make the mud flow out of the funnel.
(2) collect engineering geological data and analyze the geological conditions and construction conditions of pile position; Organize the joint review of drawings, and carry out the construction process design according to the topographic, geological and hydrological data and the elevation of pile top.
The purpose of preparation is to clarify the process flow, operation points and corresponding process standards of bored cast-in-place pile of bridge pile foundation, and guide and standardize the drilling operation construction.
Before construction, different drill bits shall be used according to different geology.
If the geological condition is good and the hole diameter or hole depth is small, take the low limit, otherwise take the high limit; (2) Main performance indexes and measurement methods of mud: ① relative density ρ x ： It can be measured by mud relative density meter.
Click the text above to pay attention to our operation instruction 1.0 for bored cast-in-place pile construction.
Table 5-1 Selection of mud performance index drilling method formation conditions mud performance index relative density viscosity (Pa.s) sand content (%) colloid rate (%) water loss rate (ml / 30min) mud thickness (mm / 30min) static shear force (PA) pH Normal circulation general stratum easy to collapse stratum 1.05 ~ 1.201.20 ~ 1.4516 ~ 2219 ~ 288 ~ 48 ~ 4 ≥ 96 ≥ 96 ≤ 25 ≤ 15 ≤ 2 ≤ 21.0 ~ 2.53 ~ 58 ~ 108 ~ 10 reverse circulation general stratum easy to collapse stratum pebble soil 1.02 ~ 1.061.06 ~ 1.101.10 ~ 1.1516 ~ 2018 ~ 2820 ~ 35 ≤ 4 ≤ 4 ≤ 95 ≥ 95 ≥ 95 ≤ 20 ≤ 20 ≤ 20 ≤ 3 ≤ 3L ~ 2.5L ~ 2.58 ~ 108 ~ 10 rotary excavation general stratum 1.02 ~ 1 1018 ~ 22 ≤ 4 ≥ 95 ≤ 20 ≤ 3L ~ 2.58 ~ 11 impact collapse prone stratum 1.20 ~ 1.4022 ~ 30 ≤ 4 ≥ 95 ≤ 20 ≤ 33 ~ 58 ~ 11 note: 1.
The drilling site shall be cleared of sundries, replaced with soft soil and compacted.
(5) erect power lines.
② Viscosity η (s) ： The site is measured with a standard funnel viscometer, as shown in Figure 7-1.
5.4 mud preparation (1) drilling mud is generally prepared from water, clay (or bentonite) and additives according to appropriate mix proportion, and its performance indexes can be selected according to the following table.
The general overburden adopts the wet rotary excavation method with static slurry wall protection, which is widely used in foundation bored pile projects such as railways, highway bridges, municipal construction, high-rise buildings and so on.
2.0 the preparation is based on technical code for construction of highway bridges and culverts and standard for quality inspection and evaluation of highway engineering 3.0.
It shall be deepened under special circumstances to ensure the smooth progress of drilling and concrete pouring.
(2) The inner diameter of the pile casing shall be at least 20cm larger than the pile diameter, the vertical line of the pile casing Center shall coincide with the pile centerline, the deviation shall not exceed 50mm, and the inclination of the vertical line shall not be greater than 1%.
(5) The buried depth of pile casing is 2 ~ 4m in dry land or island building.
4.0 construction machinery 4.1 rotary drilling rig rotary drilling rig is a construction machinery suitable for hole forming operation in foundation engineering.
For the setting of water area pile casing, it shall be strictly noted that the plane position, vertical inclination, inclination angle (inclined pile) and the connection quality of two sections of pile casing shall meet the specification requirements.
(3) The pile casing at dry land and island building can be buried by digging, and the clayey soil filled at the bottom and around the pile casing must be compacted in layers.
It has the characteristics of large installed power, large output torque, large axial pressure, flexibility and high construction efficiency, and is suitable for soil geological conditions in most areas of China.
4.3 rotary drill rotary drill is generally applicable to clay, silt, sandy soil, muddy soil, artificial backfill and stratum containing some pebbles and gravel.
When sinking, the method of weight pressing, vibration, hammering and soil removal in the cylinder can be adopted.
If the existing overhead lines, underground cables, water supply and drainage pipelines and other facilities hinder the construction or affect the safe operation, clear, relocation, protection and other measures shall be taken to properly deal with them.
The drilling rig seat should not be directly placed on the unstable fill to avoid uneven settlement.
Fill the mud cup with the mud to be measured, cover and wash the mud spilled from the small hole, then place it on the support, move the traveling code to make the lever horizontal (i.e.
The pile casing is generally rolled with steel plate, and the wall thickness ensures that the pile casing is cylindrical and does not deform.
5.3 pile casing embedding (1) a solid and watertight orifice pile casing shall be set before drilling.
For the pile casing in deep water foundation, the deviation of plane position shall also be properly adjusted to within 80mm.
At the same time, it shall also consider that the construction equipment can enter and leave the site safely.
When it is in the area affected by tide, it shall be 1.5 ~ 2.0m higher than the maximum construction water level, and measures shall be taken to stabilize the water head in the casing.
5.0 construction methods and process requirements 5.1 construction process of bored pile construction process of bored pile is shown in Figure 5-1 5.2 Preparation before construction (1) site survey shall be carried out.
the bubble is in the center), and read the scale on the left of the traveling code, which is the relative density of the mud.
For dry and hard clay, the dry rotary excavation method without stable liquid wall protection can be used.
When the site is located in shallow water, steep slope and silt, island building, sleeper or section steel can be used to set up working platform; When it is located in deep water, temporary piles can be inserted to set up a fixed working platform.
