CN1259547C - Effective length determining method for harshness coefficient size effect of rock structural face - Google Patents

Abstract

The present invention relates to an effective length determining method for harshness coefficient size effect of a rock structural surface. The method comprises the following steps: step 1, measurement sections of 10cm and 30cm are arranged on a rock structural surface which is exposed, and contour curves of the measurement sections are drawn; step 2, the fluctuation amplitude Ry0, Ry30 of the contour curves of the measurement sections of 10cm and 30cm is measured, values of harshness coefficients JRC0 and JRC30 of the measurement sections of 10cm and 30cm are calculated by a formula, and expected values E (JRC0) and E (JRC30) are solved; step 3, according to a JRC size effect fractal model, a JRC size effect fractal dimension D of the rock structural surface is solved by conversion; step 4, the D value obtained in the step 3 is inputted into a relative JRC size effect rate formula for carrying out the sensitivity analysis of a sample length Ln and a relative JRC size effect rate f, and a relation chart of Ln-f is obtained; when f is equal to 5% on the chart, a corresponding sample length on the relation chart of Ln-f is the effective length Ln<*> of the JRC size effect.

Description

The harshness coefficient size effect of rock structural face effective length is determined method

(1) technical field

The present invention relates to JRC size effect effective length and determine method, be applicable to that rock mass discontinuity with JRC size effect determines the occasion of JRC size effect effective length when the actual structure of size surface roughness coefficient of estimation.

(2) background technology

Before the present invention makes, still there is not JRC size effect effective length to determine method at present.Rock structural plane roughness coefficient (JRC) has size effect character, and natural rock mass appear generally can not the complete structural plane of exposure, structural plane roughness coefficient measurement result and JRC size effect fractal model according to the part exposure, owing to do not have JRC size effect effective length to determine method, still can't determine the roughness coefficient value of full-scale structural plane.

(3) summary of the invention

The objective of the invention is to solve owing to there is not JRC size effect effective length to determine method, and can't determine the shortcoming of full-scale structural plane roughness coefficient value, provide a kind of principle simple, easy to operate, with low cost, result of use is good, is convenient to determine that the JRC size effect effective length with different wall rock compositions, different surfaces rolling shape determines method.

JRC size effect effective length of the present invention is determined method, comprises following sequential steps:

(1) on the rock mass discontinuity of part exposure is appeared, corresponding required direction of measurement is evenly arranged statistics requisite number purpose survey section, and described survey segment length is 10cm and 30cm, adopts profilograph to draw the contour curve of above-mentioned survey section;

(2) measure the relief intensity R that above-mentioned 10cm surveys each contour curve of section _Y0, by formula ${\mathrm{JRC}}_0=49.2114e^{\frac{29}{450}}\arctan \left[\frac{{4R}_{y0}}{5}\right]$ Calculate each 10cm respectively and survey section roughness coefficient JRC ₀Value is surveyed the different roughness coefficient of section according to each 10cm and is calculated JRC ₀Expectation value E (JRC ₀);

(3) measure the relief intensity R that above-mentioned 30cm surveys each contour curve of section _Y30, by formula ${\mathrm{JRC}}_{30}=49.2114e^{\frac{29L_0}{450{\mathrm{<figure-callout\; id="30"\; label="L"\; filenames="C20041009322700061.png"\; state="\{\{state\}\}">L</figure-callout>}}_{30}}}\arctan \left[\frac{8R_{Y30}}{L_{30}}\right]$ Calculate each 30cm respectively and survey section roughness coefficient JRC ₃₀Value is surveyed the different roughness coefficient of section according to each 30cm and is calculated JRC ₃₀Expectation value E (JRC ₃₀);

(4) by rock structural plane roughness coefficient JRC size effect fractal model $E\left({\mathrm{JRC}}_{30}\right)=E\left({\mathrm{JRC}}_{10}\right){\left[\frac{L_{30}}{L_{10}}\right]}^{-D},$ Conversion obtains rock mass discontinuity JRC size effect Fractal dimensions;

(5) the relative JRC size effect of the JRC size effect Fractal dimensions value substitution rate formula that step (4) is obtained $f=\frac{{\left({0.1L}_n\right)}^{-D}-{({0.1L}_n-1)}^{-D}}{2^{-D}-1},$ Carry out sample length L _nSensitivity analysis with relative JRC size effect rate f obtains L _n-f graph of a relation (Fig. 1); At L _nOn-f the graph of a relation, when getting f=5%, L _nSample length corresponding on the-f relation curve is JRC size effect effective length L _n ^*

Employing the present invention have the following advantages: JRC size effect effective length determines that the method principle is simple, easy to operate, with low cost, result of use is good, be convenient to determine to have the JRC size effect effective length of different wall rock compositions, different surfaces rolling shape, have bigger implementary value and economic results in society.

(4) description of drawings

Fig. 1 is L _n-f graph of a relation

Fig. 2 is Xiao Langdi SSE group joint L _n-f relation curve

(5) embodiment

387 sample lengths in Xiaolangdi Dam Project wind and rain ditch west side slope rock mass SSE group joint are respectively the JRC of 10cm and 30cm contour curve ₀And JRC ₃₀Statistical measures, and the D that converts by JRC size effect fractal model ₃₀Value is listed in table 1.According to table 1 data, can draw calcareous packsand joint, clay-with-race rock joint on the strike direction and across strike direction L _n-f relation curve (Fig. 2).Can be obtained by Fig. 2, the JRC size effect effective length L of direction is moved towards at calcareous packsand joint _n ^*Be 120cm, the JRC size effect effective length L of calcareous packsand joint tendency direction _n ^*Be 110cm, the JRC size effect effective length L of direction is moved towards at clay-with-race rock joint _n ^*Be 150cm, the JRC size effect effective length L of clay-with-race rock joint tendency direction _n ^*Be 160cm.

Table 1 Xiao Langdi SSE group Joint Roughness Coefficient statistical measurements

Joint wall rock	Direction of measurement	L n＝10cm		L n＝30cm		D 30
							Sample number	JRC o	Sample number	JRC 30
		Calcareous packsand	Move towards direction	35	8.61						34	5.50	0.4079
The tendency direction	31					12.12	30	7.43	0.4454
			The clay-with-race rock	Move towards direction	88					15.83	84	11.86	0.2628
The tendency direction	82	20.48				77	15.46	0.2560

Claims (1)

1, a kind of harshness coefficient size effect of rock structural face effective length is determined method, it is characterized in that: comprise following sequential steps:

(1) on the rock mass discontinuity of part exposure is appeared, corresponding required direction of measurement is evenly arranged statistics requisite number purpose survey section, and described survey segment length is 10cm and 30cm, adopts profilograph to draw the contour curve of above-mentioned survey section;

(2) measure the relief intensity R that above-mentioned 10cm surveys each contour curve of section _Y0, by formula ${\mathrm{JRC}}_0=49.2114e^{\frac{29}{450}}\arctan \left[\frac{4R_{y0}}{5}\right]$ Calculate each 10cm respectively and survey section roughness coefficient JRC ₀Value,

Survey the different roughness coefficient of section according to each 10cm and calculate JRC ₀Expectation value E (JRC ₀);

(3) measure the relief intensity R that above-mentioned 30cm surveys each contour curve of section _Y30, by formula ${\mathrm{JRC}}_{30}=49.2114e^{\frac{29L_0}{450L_{30}}}\arctan \left[\frac{{8R}_{Y30}}{L_{30}}\right]$ Calculate each 30cm respectively and survey section roughness coefficient JRC ₃₀Value is surveyed the different roughness coefficient of section according to each 30cm and is calculated JRC ₃₀Expectation value E (JRC ₃₀);

(4) by rock structural plane roughness coefficient JRC size effect fractal model $E\left({\mathrm{JRC}}_{30}\right)=E\left({\mathrm{JRC}}_{10}\right){[-\frac{L_{30}}{L_1}]}^{-D}$ Conversion obtains rock mass discontinuity JRC size effect Fractal dimensions;

(5) the relative JRC size effect of the JRC size effect Fractal dimensions value substitution rate formula that step (4) is obtained $f=\frac{{\left(0.1L_n\right)}^{-D}-{(0.1L_n-1)}^{-D}}{2^{-D}-1},$ Carry out sample length L _nSensitivity analysis with relative JRC size effect rate f obtains L _n-f graph of a relation; At L _nOn-f the graph of a relation, when getting f=5%, L _nSample length corresponding on the-f relation curve is JRC size effect effective length L _n ^*

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