Note: a.
3.
The setting position of steel sheet pile shall meet the design requirements for earthwork construction of trench foundation, that is, there is room for formwork support and removal outside the most prominent edge of the foundation.
Including chemical composition analysis of steel, tensile and bending tests of components, locking strength test and elongation test.
The total height of stacking shall not exceed 2m.
(2) The height of the guide beam shall be appropriate, which shall be conducive to controlling the construction height of the steel sheet pile and improving the construction efficiency.
It is very important to try to reduce the soil with pile pulling.
(2) Material inspection: conduct a comprehensive test on the chemical composition and mechanical properties of the base metal of steel sheet pile.
The lifting methods include bundle lifting and single lifting.
starting point and sequence of pile pulling: for closed steel sheet pile wall, the starting point of pile pulling shall be more than 5 corner piles.
The power supply for the vibrating hammer is 1.2 ~ 2.0 times of the rated power of the vibrating hammer itself..
Otherwise, due to the vibration impact of pile pulling and too much soil with pile pulling will cause land settlement and displacement, which will bring harm to the constructed underground structure and affect the safety of adjacent original buildings, buildings or underground pipelines.
Inspection of steel sheet pile, Generally, there are material inspection and appearance inspection, so as to correct the unqualified steel sheet piles and reduce the difficulties in the process of piling.
In order to ensure the correct position of the pile sinking axis and the verticality of the pile, control the driving accuracy of the pile, prevent the buckling deformation of the sheet pile and improve the penetration capacity of the pile, it is generally necessary to set a rigid and solid guide frame, also known as “construction purlin”.
The sequence of pile pulling shall preferably be opposite to that of pile driving.
The guide frame adopts single-layer and double-sided form, which is usually composed of guide beam and surrounding purlin pile.
The spacing of sleepers is generally 3 ~ 4m, and the upper and lower sleepers shall be on the same vertical line.
2.
2.
The following points should be paid attention to when installing the guide frame: (1) use theodolite and level to control and adjust the position of guide beam.
At present, water and sand filling measures are mainly used.
(6) During the excavation of foundation trench, observe the changes of steel sheet pile at any time.
b.
The crane shall be loaded gradually with the start of the vibratory hammer, and the lifting force is generally slightly less than the compression limit of the shock absorber spring.
the welding parts that affect the driving of steel sheet piles shall be cut off; b.
In principle, the appearance quality of all steel sheet piles shall be inspected.
Interpretation of construction method Directory 1 General requirements 2 support line measurement 3 steel sheet pile mobilization and stacking area 4 steel sheet pile construction sequence 5 steel sheet pile inspection, hoisting and stacking 6 guide frame installation 7 steel sheet pile driving 8 steel sheet pile removal 1 General requirements 1.
At least one tensile and bending test shall be conducted for each specification of steel sheet pile: two test pieces shall be conducted for every 20-50t steel sheet pile.
(2) Precautions during pile pulling A.
During construction, pay attention to the following construction requirements: (1) Larsen steel sheet pile is driven by crawler excavator.
(4) The position of the guide beam shall be as vertical as possible and shall not collide with the steel sheet pile.
c.
(2) Before piling, the steel sheet piles shall be inspected one by one, and the steel sheet piles with serious corrosion and deformation at the connecting latch shall be removed.
They can be used only after they are repaired and qualified, and those that are still unqualified after repair shall be prohibited.
Cut holes and section defects shall be reinforced; c.
During the whole foundation construction period, it is strictly prohibited to collide with the support, arbitrarily remove the support, arbitrarily cut and weld on the support, and do not put heavy objects on the support during the construction operations such as excavation, hoisting, binding reinforcement and pouring concrete.
During stacking, attention shall be paid to: (1) the sequence, location, direction and plane layout of stacking shall take into account the future construction; (2) Steel sheet piles shall be stacked according to model, specification and length, and signs shall be set at the stacking place to explain; (3) Steel sheet piles shall be stacked in layers.
(4) During the insertion and driving of steel sheet piles, the inclination of each pile shall be measured and monitored.
8 removal of steel sheet piles after foundation pit backfilling, steel sheet piles shall be removed for reuse.
7 steel sheet pile driving Larsen steel sheet pile construction is related to construction water stop and safety, and is one of the most critical processes of the project.
During lifting, the number of steel sheet piles lifted each time should not be too many, and attention should be paid to protecting the lock mouth from damage.
When the deviation is too large to be adjusted by the leveling method, it must be pulled up for heavy driving.
6.
(3) Before piling, grease can be applied in the lock of steel sheet pile to facilitate the driving and pulling out of steel sheet pile.
Steel sheet piles shall be stacked on a flat and firm site where large settlement and deformation will not occur due to weight pressing, and shall be transported to the piling construction site.
If the steel sheet pile is seriously rusted, the actual section thickness shall be measured.
The mobilization time of steel sheet piles and stacking area shall be organized according to the construction schedule or site conditions to ensure that the construction of steel sheet piles meets the progress requirements.
Composite plate module shall be installed for each peripheral dimension as far as possible.
(3) The guide beam shall not sink and deform with the deepening of steel sheet pile driving.
The starting point of pile pulling can be determined according to the situation during pile sinking, and the method of jumping pulling can also be used if necessary.
Before driving, be sure to be familiar with the conditions of underground pipelines and structures, and carefully set out the accurate center line of support pile.
If there are no such steel sheet piles, they shall be sealed with auxiliary measures such as old tires or rags to avoid ground collapse due to sediment carried away by water leakage.
The spacing between surrounding purlin piles is generally 2.5 ~ 3.5m, and the spacing between double-sided surrounding wipes should not be too large.
2.
The steel sheet pile shall be hoisted and unloaded by two-point hoisting method.
For sheet piles that are difficult to pull out, the pile can be vibrated down 100 ~ 300mm with diesel hammer, and then vibrated and pulled out alternately with vibrating hammer.
(5) Closely buckle and ensure that the earth penetration after excavation is not less than 2m, so as to ensure the smooth closure of steel sheet piles; In particular, corner steel sheet piles shall be used at the four corners of the inspection well location.
The number of piles stacked in each layer shall not exceed 5.
3.
The support line shall be measured according to the requirements of the design section width of the foundation pit and trench excavation, the steel sheet pile driving position line shall be measured and set out, and the steel sheet pile driving position shall be marked with white lime.
(1) Pile pulling method the project can use the vibrating hammer to pull out the pile: the forced vibration generated by the vibrating hammer is used to disturb the soil and destroy the cohesion of the soil around the steel sheet pile, so as to overcome the pile pulling resistance and pull it out by relying on the action of additional lifting force.
Vibration driving and vibration pulling: when pulling out the pile, the lock mouth of the sheet pile can be vibrated with a vibrating hammer to reduce the adhesion of the soil, and then pull out while vibrating.
(1) Appearance inspection: including surface defects, length, width, thickness, end rectangle ratio, straightness, lock mouth shape, etc.
If there is obvious overturning or uplift, add symmetrical support at the overturning or uplift position immediately.
The stacking position of steel sheet piles shall be stacked along the support line according to the construction requirements and site conditions, so as to avoid secondary handling caused by centralized stacking.
3.
The support plane layout shape of steel sheet pile in foundation pit trench shall be as straight and tidy as possible to avoid irregular corners, so as to facilitate the utilization and support setting of standard steel sheet pile.
The guide frame is installed in the steel sheet pile construction.
Before pulling out the steel sheet pile, carefully study the pile pulling method sequence, pile pulling time and soil hole treatment.
4 steel sheet pile construction sequence positioning and setting out – trench excavation – Installation of guide beam – driving steel sheet pile – removal of guide beam – purlin and support construction – earthwork excavation – foundation construction (force transfer belt) – removal of support – basement main structure construction – earthwork backfilling – pulling out steel sheet pile – clearance treatment after pulling out steel sheet pile 5 inspection, hoisting and stacking of steel sheet pile 1.
Generally, it is 8 ~ 15mm thicker than the sheet pile wall.
Sleepers shall be placed between each layer.
d.
Steel cables are usually used for bundle hoisting, while special lifting tools are commonly used for single hoisting.
