Basic provisions of light probe: filling embankment foundation bearing capacity requirements f0 analysis: When the embankment height ≤2.0m, according to the road bed stability compaction strength requirements to consider. Calculated load: When the embankment height is less than 2.0m, the load is calculated according to the operation period; When the embankment height is > 2.0m, the load is calculated according to the construction period. The self-weight stress of embankment base is considered according to Z maximum stress. The following three commonly used dynamic penetration test equipment are used for foundation bearing capacity test, and the relevant parameters are shown in the following table: Heavy penetration instrument railway. The load of embankment during construction period only considers the embankment self-weight; Operational load includes embankment.
Basic provisions:
f0 analysis of bearing capacity requirements of embankment foundation: When the embankment height is ≤2.0m, it is considered according to the requirements of stability compaction degree and strength of highway road bed. Calculated load: When the embankment height is less than 2.0m, the load is calculated according to the operation period; When the embankment height is > 2.0m, the load is calculated according to the construction period. The self-weight stress of embankment base is considered according to the large stress.
The following three commonly used dynamic penetration test equipment are used for the foundation bearing capacity test, and the relevant parameters are as follows: Heavy penetration instrument railway.
The load of embankment during construction only considers the embankment self-weight; The load during operation includes the dead weight of embankment, road surface and running load, among which the running load is only considered as static load and considered as equivalent static soil column action.
Traffic load: Class I highways and expressways according to Class I standards; Highways of Grade II and below shall be subject to Grade II standards. Pavement structure: first-class highways and expressways are considered according to the total thickness of 78cm; The total thickness of the secondary highway is 55cm. Grade 3 and below are considered according to the total thickness of 40cm. Heavy gauge railway.
Note:
When in use, make the core hammer fall freely, the fall height is 50 cm, and the number of hammering per 30 cm of human soil layer is N100.
Operating procedures:
First drill to the test soil level with light drill.
Before filling, the probe frame should be installed smoothly and keep the probe hole vertical.
When filling, make the core hammer fall freely. The drop distance is 76cm, the penetration depth, the penetration amount of a burst and the corresponding hammer number are recorded in time (generally 5 hits are a burst), and the measured hammer number N for every 10cm of penetration is calculated.
When the length of the probe rod is greater than 2m, the number of hammering should be corrected according to the corresponding specifications.
About:
The product uses certain hammering kinetic energy to make engineering geological evaluation of foundation soil. To standardize the roadbed in the construction of highway engineering in our country
Parameters:
Weight: 10kg+10g.
Drop height: 500mm.
Large penetration depth: 6000mm.
Penetration of the hammer: 60 degrees.
Large diameter of injection hammer Angle: 40mm.
Light weight: 10KG.
Other notes:
Identification method of unsuitable soil
(1) The identification of unsuitable soil is determined by the Dutch type light dynamic probe, and the hammer number of 20cm penetration is less than the hammer number required in the above table.
(2) When the use of this method is controversial, the sample should be taken for water content and pore ratio test, when the test results meet the natural water content is greater than or equal to the liquid limit and the natural pore ratio is greater than or equal to 1.0, it is judged to be unsuitable soil.
Determination of unsuitable soil depth
The Dutch type light dynamic penetration test results are expressed as follows: when the penetration depth is h, the corresponding hammer number N20 (strike times /20cm) is greater than or equal to the standard number of hammer strikes of unsuitable soil required in the table above, then the penetration depth h is the unsuitable soil depth.
Basic requirements for the operation of the Dutch light power probe
The contractor shall trench drainage before the construction of unsuitable ground foundation. Within the scope of the red line, grid drainage ditches shall be excavated according to the standards of transverse spacing less than 10m, trench bottom width 0.3m and depth 0.6m. The longitudinal drainage ditches on both sides of the red line shall be deepened. The test shall be carried out after at least 3 consecutive sunny days after drainage.
How it works:
It is a kind of in-situ testing method to judge the property of soil by using a certain drop hammer energy and the degree of penetration of a conical probe of a certain size into the soil.
Structure composition:
It is mainly composed of three parts: the pointed cone head, the feeler rod and the core hammer. The hammer weighs 10 kg.
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