Method of evaluating relative compaction of calcium soil on the basis of dynamic penetration index calibration system

A technology of relative density and dynamic penetration testing, which is applied in the direction of applying repeated force/pulsation force to test material strength, strength characteristics, and measuring devices. It can solve the problems of site engineering design and construction inconvenience, and many expressions, and achieve easy Operation, precise relative density, simple and clear method

Inactive Publication Date: 2019-01-29
TIANJIN UNIV
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

Therefore, there are many and complicated expressions related to it in the industry, wh

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  • Method of evaluating relative compaction of calcium soil on the basis of dynamic penetration index calibration system
  • Method of evaluating relative compaction of calcium soil on the basis of dynamic penetration index calibration system
  • Method of evaluating relative compaction of calcium soil on the basis of dynamic penetration index calibration system

Examples

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Embodiment 1

[0083] The method for predicting the relative compactness of carbonate sand foundation soil based on the dynamic penetration test index of the present invention adopts the following steps:

[0084] Step 1, the calcareous soil samples retrieved from the site are divided into two types, one is calcareous gravel, and its maximum dry density ρ d,max =1660kg / m 3 , the minimum dry density ρ d,min =1273kg / m 3 , average particle size d 50 =2.7mm, uneven coefficient C u =6.25; the other type is calcareous coarse sand, whose maximum dry density ρ d,max =1567kg / m 3 , the minimum dry density ρ d,min =1250kg / m 3 , average particle size d 50 =0.9mm, non-uniformity coefficient C u = 3.33.

[0085] Step 2, set nine relative compactness D for each type of calcareous soil sample ri , according to the maximum dry density ρ measured in step 1 d,max , minimum dry density ρ d,min , using the formula (1) to calculate various relative compactness D ri Dry density ρ of each type of calcare...

Embodiment 2

[0103] This embodiment is further limited on the basis of Embodiment 1. In a field test in the South China Sea, the heavy-duty dynamic penetration test was used to predict the compactness of the seabed calcareous soil foundation. p =63.5kg, drop hammer height h p =760mm, probe diameter d p =74mm, the penetration index is probe penetration D sp =Number of hammer blows required for 100mm 63.5 , and substituting it into formula (7), we can get

[0104] N 63.5 =0.118N 10 (8)

[0105] Then substitute formula (8) into the obtained in step 7 with D ri The expression of the relationship between can be obtained:

[0106]

[0107] Such as Figure 6 As shown, according to the penetration index of the heavy-duty dynamic penetration test on site, the relative compactness of the foundation soil predicted by formula (6) is compared with the field results, and the difference is not large. The reason is that the present invention is aimed at the calcareous soil foundation, and ...

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Abstract

The invention discloses a method of evaluating relative compaction of calcium soil on the basis of a dynamic penetration index calibration system. The method include: A) drying a calcium soil sample and determining [rho]<d, max>, [rho]<d, min>, d<50> and C; B) calculating the [rho]di of each type of the calcium soil sample under every Dri; C) testing the penetrating hammer striking time of eachtype of the calcium soil sample and the accumulated penetrating depth of a probe; D) respectively drawing hammer striking time-accumulated penetrating depth scatter diagrams, and fitting the slope p<index, i> of each straight line; E) acquiring [p<index, i>SQRT(d<50>C), Dri], and drawing a scatter diagram; F) performing fitting to obtain an expression formula of p<index, i>SQRT(d<50>C) andDri; G) acquiring an expression formula of relationship between 300[SQRT(d<50>C)]/N10 and the Dri; H) expressing the physical quantities by means of absolute coefficient fundamental dimensions; I)according to the dimensions of the physical quantities, forming a dimension matrix and calculating [pi]1 and [pi]2; J) determining the relationship between dynamic penetration test physical quantitiesand light dynamic penetration test physical quantities; K) deriving a penetration index of the dynamic penetration test; and L) substituting the index into the expression formula, thus obtaining a new expression formula.

Description

technical field [0001] The invention relates to a method for evaluating the relative compactness of calcareous soil, more specifically, relates to a method for evaluating the relative compactness of calcareous soil based on a dynamic penetrating sounding index calibration system. Background technique [0002] Calcareous soil foundations are widely distributed along the continental shelf and coastline. Due to the unique physical and mechanical properties of calcareous soil, its engineering characteristics are quite different from continental sediments. Therefore, it is very important to propose a new method that can quickly and accurately predict the relative compactness of calcareous soil foundations for the design and construction of site engineering in these areas. [0003] For non-cohesive soils such as calcareous gravel and calcareous sand, the relative compactness D r It is the main index to evaluate the degree of compaction. D. r The calculation formula of is as fo...

Claims

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Application Information

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IPC IPC(8): G01N3/34
CPCG01N3/34G01N2203/0005G01N2203/0039G01N2203/0682
Inventor 李飒林澜刘鑫刘小龙俞俊
Owner TIANJIN UNIV
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