Shanghai Strong foundation Large diameter vibrating immersed tube rubble pile, the maximum pile diameter can be reached1200mm, pile length can exceed30m, gravel pile equipment can not only be applied to land foundation treatment, but also applied to water foundation treatment (using our thousand ton engineering ship as the carrier), to meet more and more water foundation treatment projects.
Before the construction of gravel pile, the pile forming test must be carried out, and the number of piles should be 9-16The root. If it is found that the quality does not meet the design requirements, the pile spacing, the amount of gravel, the vibration frequency, the vibration retention time, the reverse insertion depth and other parameters should be adjusted. The soil between piles is mainly tested by standard penetration method supplemented by other test methods. The construction process must be strictly implemented, the construction record must be checked, the completion of the construction must be tested, to test the treatment effect.
1And inspection method for construction quality of gravel pile
Test stage of crushed stone pile: before and after the test pile, the soil between piles is tested by standard penetration, static penetration and instantaneous Rayleigh wave method. The gravel pile adopts dynamic probe (heavyIIMethod type); The static load tests of single pile and three pile composite foundation were carried out respectively. Normal construction phase: only standard penetration, static penetration, instantaneous Rayleigh wave and dynamic penetration test work.
2, gravel pile construction quality inspection time
In the pile15It will take place in a few days.
3And inspection frequency of gravel pile construction quality
Pile test stage: Before pile test, standard penetration, static penetration and instantaneous Rayleigh wave tests are carried out respectively, with no less than each test section5A point; After test pile, standard penetration test according to the number of gravel pile root1%Set up measuring points; Static penetration test3point/5000㎡, when the area of the station is less than5000㎡, is not less than3Point; Instantaneous Rayleigh wave detection longitudinal1point/40m, the detection points are randomly arranged.
The dynamic penetration probe was detected around the point where the penetration number of soil mark between piles could not reach the requirement2-3Root piles. The static load test is carried out in the first test section, pile head and composite foundation respectively2Points.
Normal construction stage: standard penetration test according to the number of gravel pile root1%Set up measuring points; Static penetration test3point/5000㎡; Instantaneous Rayleigh wave test1point/40m; dynamic2-3%.
4, quality inspection standard for rubble pile construction
Standard penetration test: the number of standard penetration hits between piles of treated fine sand, silty sand and silt soil layer was measuredN63.5Should not be less than the critical standard penetration of liquefaction of the section.
Instantaneous Rayleigh wave method: the shear wave velocity of the liquefiable soil layer such as fine sand, silty sand and silt after foundation treatment is not less than200m/s; The shear wave velocity of silt clay interlayer after foundation treatment is not less than150m/s; The shear wave velocity of clay interlayer after foundation treatment is not less than170m/s.
Static penetration detection:Interpile resistance of fine sandqcNot less than9Mpa;In sandy soil and sub-sandy soil layerqcNot less than6.5Mpa;Subclay, clay layerqcNot less than1.4Mpa; A silty clay layerqcNot less than0.9Mpa;Silt layerqcNot less than0.8Mpa;
Power touch (heavyIIType):continuous5The amount of sink when hit should not be greater than10cm.
Static load test:The allowable bearing capacity of single pile and three pile composite foundation were detected300Kpaand150Kpa.
Shanghai Qiangqiang Foundation Engineering Co., LTD. 's business covers foundation pit engineering, pile foundation engineering, land and water Foundation treatment, slope treatment and other engineering fields. Around"Excellent technology, reliable process ", construction fast "technical requirements,Is to provide customers with land, water foundation engineering technical consultation, construction services and other comprehensive solutions of the entity enterprise.Contact Number:400-1002850
