Super long rod heavy-type/super heavy-type cone dynamic penetration blow counts correction method

Abstract

The invention discloses a super long rod heavy-type / super heavy-type cone dynamic penetration blow counts correction method. The method comprises the following steps: 1) arranging strainmeters on a detecting rod, the strainmeters are arranged on the detecting rod at intervals; 2)according to requirement of a cone dynamic penetration test technology prescribed in Geotechnical Engineering Test Monitoring Manual, performing on-site tests, recording the blow counts when penetration depth is 10 cm for each time, storing the strain value at a measuring point of the strainmeter when each time of hammering is carried out; 3) establishing a cone dynamic penetration value calculating model; 4) determining a damping coefficient; and 5) using the obtained damping coefficient and performing the value test with the rod having length of 20-120 m, calculating impact force and effective energy at the bottom of the rod, and obtaining the blow counts correction coefficient. The invention provides the calculating method of heavy-type / super heavy-type cone dynamic penetration blow counts correction coefficient of the rod having length of 20 m, which fills the epitaxial blank of the dynamic penetration blow counts correction coefficient in domestic geotechnical engineering investigation.

Description

technical field [0001] The invention relates to an in-situ testing technology, in particular to a method for correcting the number of impacts of super-long rod heavy-duty and super-heavy cone dynamic penetration testing. Background technique [0002] At present, my country's hydropower development is mainly concentrated in the western region. Due to frequent tectonic activities, strong river action, and frequent geological disasters in the western region, the riverbed cover layer is often thick (generally tens of meters or even hundreds of meters thick), and its causes are complicated. (Alluvial, alluvial, slope deposits, colluvial deposits, landslide accumulation mixed), loose structure (granular, no cementation), coarse particles (mainly eggs, gravel or broken, block stones and other coarse grains), spatial variation Big. The deep overburden of the riverbed is a granular material, and it is difficult to drill (borrow) and take the original sample. The acquisition of its phy...

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Problems solved by technology

[0003] According to the "Code for Geotechnical Engineering Investigation" (GB50021-2001), the scope of application of heavy-duty and super-heavy cone dynamic penetration testing is respectively 20m long rod, 50 hammer strokes and 19m long rod, 40 hammer strokes. Meet the needs of in-situ testing in areas with deep overburden

For problems beyond the scope of application of the standard, the scope of application of the length of the conical dynamic penetrating probe and its correction, except for some simple solutions proposed by some scholars, there is not only no mature experience for reference and recognized standards to rely on, but also few studies.

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