阅读说明：本技术 利用岩体波速计算帷幕灌浆岩体裂隙充填率的方法 (Method for calculating crack filling rate of curtain grouting rock mass by using rock mass wave velocity ) 是由 蔡耀军 刘海涛 徐复兴 王小波 吴蒙蒙 徐伟 于 2019-11-06 设计创作，主要内容包括：本发明提供一种利用岩体波速计算帷幕灌浆岩体裂隙充填率的方法,包括如下步骤：步骤一、利用岩体二相关系推导出灌浆后岩体裂隙充填比率计算公式,步骤二、将测试的灌前岩体波速数据按从小到大排序,并统计各波速数据的数量,计算各波速值所占比率；步骤三、使用岩体波速线性分级结合泊松分布概率密度函数构建岩体波速泊松分布概率密度公式,拟合灌前岩体波速比率数据,得到工区岩块波速数值；步骤四、将各速度参数代入步骤一公式中,计算岩体裂隙充填比率。本发明只根据工区帷幕灌浆前、后岩体波速值计算水利工程中帷幕灌浆后岩体裂隙充填率,既可为评价帷幕灌浆质量提供量化指标,也可减少工地现场试验工作量,显著提高工效。(The invention provides a method for calculating the crack filling rate of curtain grouting rock by using the wave velocity of rock, which comprises the following steps: step one, deducing a calculation formula of the filling ratio of the rock mass fracture after grouting by using a rock mass two-phase relation, and step two, sequencing the tested wave velocity data of the rock mass before grouting from small to large, counting the number of the wave velocity data, and calculating the ratio of the wave velocity values; thirdly, constructing a rock mass wave velocity poisson distribution probability density formula by using linear grading of rock mass wave velocity and poisson distribution probability density function, and fitting rock mass wave velocity ratio data before irrigation to obtain a rock mass wave velocity numerical value of a work area; and step four, substituting each speed parameter into the formula in the step one, and calculating the rock mass fracture filling ratio. According to the method, the rock mass crack filling rate after curtain grouting in the hydraulic engineering is calculated only according to the wave velocity values of the rock masses before and after curtain grouting in the work area, so that quantitative indexes can be provided for evaluating the curtain grouting quality, the workload of site test in a construction site can be reduced, and the work efficiency is obviously improved.)

1. A method for calculating the crack filling rate of curtain grouting rock mass by using the wave velocity of the rock mass is characterized by comprising the following steps:

step one, deducing a rock mass fracture filling ratio calculation formula (formula 4) after grouting by using a rock mass two-phase relation:

in the formula: vr represents the wave velocity of the rock block in the work area; v_wRepresents the wave velocity of water; v_cRepresents the wave velocity of the cement; v_qRepresenting the average wave velocity of the rock mass before irrigation; v_hRepresenting the average wave velocity of the rock mass after irrigation; l represents the length of the rock mass; lw represents the crack width; lr represents the width of the rock mass; lc represents the width of a cement filling crack; Lw/L represents the rock mass fracture ratio; Lc/Lw represents a crack filling ratio after grouting;

step two, sequencing the tested wave velocity data of the rock mass before grouting from small to large, counting the number of the wave velocity data, calculating the ratio of the wave velocity values, calculating the average value of the wave velocity of the rock mass before grouting and the wave velocity of the rock mass after grouting in the work area, and drawing a wave velocity ratio curve of the rock mass before grouting;

thirdly, constructing a rock mass wave velocity poisson distribution probability density formula by using linear grading of rock mass wave velocity and poisson distribution probability density function, and fitting rock mass wave velocity ratio data before irrigation to obtain a rock mass wave velocity numerical value of a work area;

and step four, substituting the wave velocity values of the rock mass of the work area obtained in the step three and other various velocity parameters into the calculation formula (4) of the crack filling ratio of the grouted rock mass deduced in the step one, and calculating the crack filling ratio of the grouted rock mass of the whole work area.

2. The method for calculating the crack filling rate of curtain grouting rock mass by using the wave velocity of the rock mass as claimed in claim 1, wherein: the first step is specifically as follows:

deducing the fracture ratio in the rock mass according to the relation between the distance and the speed, namely an expression (1), and obtaining an expression (2):

after grouting, filling slurry in the rock mass crack, and deducing the crack filling ratio after grouting according to the relation between the path and the speed, namely formula (3) and combined formula (2), wherein the formula (4) is as follows:

3. the method for calculating the crack filling rate of curtain grouting rock mass by using the wave velocity of the rock mass as claimed in claim 1, wherein: the third step is specifically as follows:

and (3) utilizing the mirror image similarity between the wave velocity ratio curve of the rock mass before irrigation drawn in the step two and the common poisson distribution curve, substituting the linear grading relation of the wave velocity of the rock mass shown in the formula (6) into the poisson distribution probability density function shown in the formula (5), constructing a probability density relation of the wave velocity poisson distribution of the rock mass shown in the formula (7), fitting the wave velocity of the rock mass before irrigation by using the probability density function of the poisson distribution of the wave velocity of the rock mass, and determining the wave velocity value of the rock mass in the work area when the fitting error is minimum:

k＝-(V-V_r)/σ (6)

in the formula: p (X ═ k) represents the probability of a certain event X occurring k times in uniform time, space; k represents the number of times; λ represents the Poisson distribution expectation; v represents the wave velocity of the rock mass in the work area; vr represents the wave velocity of the rock block in the work area; σ represents a velocity classification value; p (V) represents the probability that the wave velocity of the rock mass in the unit space of the work area is V.

Technical Field

The invention relates to the technical field of engineering detection, in particular to a method for calculating the crack filling rate of curtain grouting rock mass by using the wave velocity of the rock mass.

Background

At present, in the detection of the grouting construction quality of a hydropower engineering curtain, the water permeability of a pressurized water test is specified as a quantitative index in regulations and specifications, and the defect of single index exists.

The water pressure test relates to many equipment (drilling machine, water pump, water pressure instrument, pressure gauge, flowmeter, etc.), and the test time is long, and the cost is high. In actual detection work, geophysical prospecting detection is assisted, but various geophysical prospecting detection methods usually detect physical property parameter values (such as wave velocity, resistivity and the like) of a medium (rock mass), cannot be quantized into concrete parameters of grouting construction quality, can only be used as an auxiliary means, and cannot exert the advantages of high geophysical prospecting detection cost ratio and high efficiency.

Disclosure of Invention

The invention aims to provide a new curtain grouting quality evaluation index, namely rock mass fracture filling rate, and provides a calculation method of the index, wherein the rock mass fracture filling rate is calculated according to the acoustic velocity of a work area rock mass before and after grouting.

The technical scheme of the invention is realized as follows:

a method for calculating the crack filling rate of curtain grouting rock by using the wave velocity of the rock comprises the following steps:

step one, deducing a rock mass fracture filling ratio calculation formula (formula 4) after grouting by using a rock mass two-phase relation:

in the formula: vr represents the wave velocity of the rock block in the work area; v_wRepresentsThe wave velocity of the water; v_cRepresents the wave velocity of the cement; v_qRepresenting the average wave velocity of the rock mass before irrigation; v_hRepresenting the average wave velocity of the rock mass after irrigation; l represents the length of the rock mass; lw represents the crack width; lr represents the width of the rock mass; lc represents the width of a cement filling crack; Lw/L represents the rock mass fracture ratio; Lc/Lw represents a crack filling ratio after grouting;

step two, sequencing the tested wave velocity data of the rock mass before grouting from small to large, counting the number of the wave velocity data, calculating the ratio of the wave velocity values, calculating the average value of the wave velocity of the rock mass before grouting and the wave velocity of the rock mass after grouting in the work area, and drawing a wave velocity ratio curve of the rock mass before grouting;

thirdly, constructing a rock mass wave velocity poisson distribution probability density formula by using linear grading of rock mass wave velocity and poisson distribution probability density function, and fitting rock mass wave velocity ratio data before irrigation to obtain a rock mass wave velocity numerical value of a work area;

and step four, substituting the wave velocity values of the rock mass of the work area obtained in the step three and other various velocity parameters into the calculation formula (4) of the crack filling ratio of the grouted rock mass deduced in the step one, and calculating the crack filling ratio of the grouted rock mass of the whole work area.

Further, the first step specifically comprises:

deducing the fracture ratio in the rock mass according to the relation between the distance and the speed, namely an expression (1), and obtaining an expression (2):

after grouting, filling slurry in the rock mass crack, and deducing the crack filling ratio after grouting according to the relation between the path and the speed, namely formula (3) and combined formula (2), wherein the formula (4) is as follows:

further, the third step is specifically as follows:

and (3) utilizing the mirror image similarity between the wave velocity ratio curve of the rock mass before irrigation drawn in the step two and the common poisson distribution curve, substituting the linear grading relation of the wave velocity of the rock mass shown in the formula (6) into the poisson distribution probability density function shown in the formula (5), constructing a probability density relation of the wave velocity poisson distribution of the rock mass shown in the formula (7), fitting the wave velocity of the rock mass before irrigation by using the probability density function of the poisson distribution of the wave velocity of the rock mass, and determining the wave velocity value of the rock mass in the work area when the fitting error is minimum:

k＝-(V-V_r)/σ (6)

in the formula: p (X ═ k) represents the probability of a certain event X occurring k times in uniform time, space;

k represents the number of times; λ represents the Poisson distribution expectation; v represents the wave velocity of the rock mass in the work area; vr represents the wave velocity of the rock block in the work area; σ represents a velocity classification value; p (V) represents the probability that the wave velocity of the rock mass in the unit space of the work area is V.

The invention has the advantages that:

1. at present, the common means for knowing the filling condition of the rock mass fracture after grouting comprises drilling coring and in-hole television observation, the rock mass is severely disturbed in the drilling process, the rock mass is easy to fracture at the fracture, and after fracture, mutual friction and collision are caused, so that cement filled in the fracture falls off from the rock mass, and after grinding, the cement filled in the rock mass fracture after grouting is difficult to observe after coring. When the hole wall is observed by a television in the hole, cement filled in cracks of rock mass on the hole wall is broken due to the friction between the drill bit and the hole wall and is lost along with circulating water, so that the crack filling condition is difficult to accurately count. The method calculates the fracture filling condition by measuring the change of the wave velocity of the rock mass before and after grouting, avoids the defects of drilling coring and in-hole television observation, and provides a more accurate rock mass fracture filling calculation method after grouting.

2. The invention provides a quantifiable index capable of evaluating curtain grouting construction quality, namely rock mass crack filling rate, which can be combined with water permeability to comprehensively evaluate the curtain grouting construction quality and can be applied and verified in hydraulic engineering such as geophysical prospecting detection of engineering dam curtain grouting engineering for comprehensively treating (rebuilding) a full hydropower station.

3. The calculation formula of the filling rate of the grouting cracks of the rock mass is derived by using the biphase property of the rock mass. And (3) building a rock mass wave velocity poisson distribution probability density formula by combining the rock mass wave velocity linear grading with the poisson distribution probability density formula, combining the rock mass wave velocity before grouting in the work area with the poisson distribution, and calculating statistical parameters of the rock mass wave velocity before grouting in the work area, such as the expected value of the work area rock mass wave velocity poisson distribution, the rock mass wave velocity grading value and the like.

4. The wave velocity value of the rock mass in the work area is determined on the basis of mathematical statistics, and the more the wave velocity test value of the rock mass before irrigation is, the more the result can truly show the actual condition of the rock mass in the work area. The invention can correct the rock mass wave velocity value in time along with the increase of the rock mass wave velocity value participating in calculation. The wave velocity value of the rock mass in the work area is determined without field tests such as sampling and sample preparation, and a plurality of factors which possibly influence the accurate determination of the wave velocity value of the rock mass due to loss of confining pressure, sampling position, sampling quantity and the like of a sample are avoided.

5. The calculation method is practical, simple and convenient, rapid in calculation and easy to popularize. Through the practical application of a plurality of work areas and the mutual comparison and verification with the drilling coring result and other geophysical prospecting methods (borehole television in-hole observation), the calculated rock fracture filling rate after grouting is 16-35% higher than that of the drilling coring method and 11-26% higher than that of the in-hole television observation method, and the rock fracture filling condition after grouting can be more truly reflected.

Drawings

FIG. 1 is a working schematic diagram of the method for calculating the crack filling rate of curtain grouting rock mass by using the wave velocity of the rock mass;

FIG. 2 is a schematic diagram of a two-phase rock mass according to an embodiment of the present invention, wherein FIG. 2(a) is before grouting and FIG. 2(b) is after grouting;

FIG. 3 is a wave velocity ratio curve of rock mass before and after grouting in the embodiment of the invention;

FIG. 4 is a graph of wave velocity ratio of rock mass before grouting and common Poisson distribution ratio in the embodiment of the invention, wherein FIG. 4(a) is the wave velocity ratio of rock mass before grouting, and FIG. 4(b) is the Poisson distribution ratio;

FIG. 5 is a comparison graph of a poisson fitting curve of rock mass wave velocity and a test curve of rock mass wave velocity before irrigation in the embodiment of the invention.

Detailed Description

The technical solution of the present invention will be clearly and completely described below with reference to the accompanying drawings.

The invention provides a method for calculating the crack filling rate of curtain grouting rock by using the wave velocity of rock, which comprises the following steps:

step one, deducing a rock mass fracture filling ratio calculation formula after grouting by using a rock mass two-phase relation.

During drilling sound wave test, the periphery of the hole wall can be regarded as a rock block, a structural surface and a crack before grouting, and the crack is filled with water; after grouting, the periphery of the hole wall can be regarded as a rock block, a structural surface and a crack (the part filled with cement is filled with water, and the part not filled with the cement is filled with water), as shown in figure 1.

Referring to the three-phase diagram of soil in soil mechanics, the underground rock mass before grouting is regarded as two phases of rock mass and water, and a two-phase diagram is shown in fig. 2 (a).

According to the relation between the distance and the speed, namely the equation (1), the fracture ratio in the rock body can be deduced, namely the equation (2).

After grouting, the rock fractures are partially filled with slurry, as shown in fig. 2 (b). And deducing the fracture filling ratio after grouting according to the relation between the path and the speed, namely the formula (3) and the combined formula (2), see the formula (4).

In the formula: vr represents the wave velocity of the rock block in the work area; v_wRepresents the wave velocity of water; v_cRepresents the wave velocity of the cement; v_qRepresenting the average wave velocity of the rock mass before irrigation; v_hRepresenting the average wave velocity of the rock mass after irrigation; l represents the length of the rock mass; lw represents the crack width; lr represents the width of the rock mass; lc represents the width of a cement filling crack; Lw/L represents the rock mass fracture ratio; Lc/Lw represents a crack filling ratio after grouting.

And step two, sequencing the tested wave velocity data of the rock mass before grouting from small to large, counting the number of the wave velocity data, calculating the ratio of the wave velocity values, calculating the average value of the wave velocity of the rock mass before grouting and the wave velocity of the rock mass after grouting in the work area as shown in table 1, and drawing a wave velocity ratio curve of the rock mass before grouting, wherein the wave velocity ratio curve is shown in figure 3.

The lithology of the work area is metamorphic conglomerate, the grouting is III-order construction, the grouting hole distance is 2m, and the grouting pressure is 3 MPa. Pilot holes are adopted for detecting the wave velocity of the rock mass before work area grouting, 25 holes are tested in total, 7370 test points are tested, and the average value Vq of the wave velocity of the rock mass before work area grouting is 5267 m/s; and the wave velocity detection of the rock mass after grouting is positioned in the middle of a grouting hole (1 m away from a pilot hole for testing before grouting), 24 holes are tested after grouting, 7129 test points are tested, and the average value Vh of the wave velocity of the rock mass after grouting is 5430 m/s.

TABLE 1 rock mass acoustic velocity statistical table before irrigation

And step three, utilizing the mirror image similarity (see fig. 4) between the wave velocity ratio curve of the rock mass before irrigation obtained in the step two and the common poisson distribution curve, substituting the linear classification relation of the wave velocity of the rock mass shown in the formula (6) into the poisson distribution probability density function shown in the formula (5), constructing a probability density relation of the wave velocity poisson distribution of the rock mass shown in the formula (7), fitting the wave velocity test ratio data of the rock mass before irrigation, and determining the wave velocity value of the rock mass in the work area when the fitting error is minimum.

k＝-(V-V_r)/σ (6)

In the formula: p (X ═ k) represents the probability of a certain event X occurring k times in uniform time, space; k represents the number of times; λ represents the Poisson distribution expectation; v represents the wave velocity of the rock mass in the work area; vr represents the wave velocity of the rock block in the work area; σ represents a velocity classification value; p (V) represents the probability that the wave velocity of the rock mass in the unit space of the work area is V.

In a uniform space and time range, the occurrence probability of random events accords with a Poisson distribution rule. The structural surface and the cracks of the rock mass are distributed irregularly; the test holes are approximately uniformly distributed along the horizontal direction of the grouting axis of the work area; the curtain grouting depth is different from the geological conditions, the design anti-seepage standard and other reasons, and the test points are also approximately uniformly distributed in the vertical direction of the grouting axis, so that the wave velocity ratio of the rock mass before the grouting in the work area accords with the Poisson distribution rule. After grouting, the wave velocity of the rock mass in the work area is filled by the grouting slurry, the ratio curve deforms (see figure 3), and the distribution of the ratio curve is different from that of Poisson.

And (3) fitting the acoustic velocity of the rock mass before filling according to the formula (7), wherein when the lambda is 2.3, the Vr is 5590m/s, and the sigma is 130m/s, the error is minimum. The fitted wave velocity values are shown in table 2, and the fitted wave velocity probability curves are shown in fig. 5.

TABLE 2 Poisson fitting rock mass acoustic velocity value table

And step four, substituting the wave velocity values of the rock mass of the work area obtained in the step three and other various velocity parameters into the calculation formula (4) of the crack filling ratio of the grouted rock mass deduced in the step one, and calculating the crack filling ratio of the grouted rock mass of the whole work area.

Wave velocity V of water_WTake 1450m/s and the wave velocity V of cement_CThe wave velocity V of the rock mass is fitted by taking 3720m/s (test result of manufacturing cement test block under field grouting pressure)_rAnd taking 5590m/s, wherein the average wave velocity Vq of the rock mass before grouting is 5267m/s, the average wave velocity Vh of the rock mass after grouting is 5430m/s, and calculating the fracture filling ratio of the rock mass in the work area after grouting to be 63.1%. After the curtain grouting of the work area is carried out on the wave velocity of the rock mass, 63.1% of rock mass fracture space is filled with cement, the statistical fracture filling rate of the drilling coring of the work area is 34.2%, and the observed fracture filling rate in the television hole of the drilling of the work area is 47.0%.

And when the wave velocity test of the rock mass before and after grouting is carried out on the same hole, calculating the rock mass fracture filling rate after grouting according to the wave velocity values before and after grouting at the same measuring point. When the wave velocity value of the rock mass before irrigation is larger than the wave velocity value of the fitting rock mass, the rock mass at the point is considered to be complete and has no cracks; and when the calculated value of the fracture filling rate is more than 100%, checking the wave velocity test values of the rock mass before and after grouting.

The above description is only an embodiment of the present invention, but the scope of the present invention is not limited thereto, and any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present invention are included in the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.