CN104075747B - Define and calculate and ram the heavy method than evaluation hammer ram conversion usefulness - Google Patents

Abstract

The present invention defines and calculates and rams the heavy ratio method evaluating hammer ram conversion usefulness, belongs to civil engineering groundwork processing technology field；Technical problem to be solved is to provide a kind of heavy ratio of definition rammer, and with hammer ram as object of study, calculates the method rammed heavy ratio and evaluate tamping efficiency；The technical scheme is that the test of ramming by many group hammer rams, definition also calculates each group of heavy ratio of rammer respectivelyDrawing heavy the combination than curve chart of ramming times rammer to contrast to evaluate the conversion usefulness of hammer ram, wherein b is to measure gained to click ramming volume, and S is the hammer ram travel values calculated by integrating meter；The present invention compares λ by calculating to ram to sink, obtain ramming times to ram and heavy compare curve, cross and many group hammer ram gained ramming times are rammed heavy ratio curve comparison analysis, realize the quantitative assessment of strong rammer usefulness, consolidation effect, design optimization and strong rammer lectotype selection for basement process provide reference, method is simple, explicit physical meaning, calculates the most convenient economy.

Description

Define and calculate and ram the heavy method than evaluation hammer ram conversion usefulness

Technical field

The present invention defines and calculates and rams the heavy ratio method evaluating hammer ram conversion usefulness, belongs to civil engineering groundwork processing technology field, It is specifically related to the usefulness conversion aspect of hammer ram.

Background technology

Heavy-tamping method is that tens tons of (generally 8-40t) weights are freely fallen by one from tens meters of (general 6-40m) eminences, right Foundation soil carries out compacted, the method for strong compaction.Present case is, strong rammer Practice Development is fast, and heavy tamping theory and design reason In place of opinion still has many ambiguous, theory lags far behind practice, and the problem such as the energy distribution of strong rammer, construction optimization is the most standby Concerned.

Strong rammer is presently mainly with the soil body of consolidated subsoil as object, detects and evaluates the consolidation effect of the soil body, but cannot comment The efficiency conversion of hammer ram self during valency strong rammer, for the efficiency conversion of hammer ram, lacks a kind of evaluation methodology.Strong rammer impact ground is One complicated problem, strong rammer process is an extremely complex non-linear process, the most still do not have a set of maturation theory and Computational methods.Interaction between hammer ram and stratum is the important content of foundation dynamic compaction treatment effect research, checks on impact Effect can align the confirmation knowledge aspect such as tamping efficiency, energy expenditure and be beneficial to, and comes from hammer ram impact ground angle for carrying out further Understanding forced ramming reinforcing effect mechanism research provides help, does corresponding guidance for the aspect of actual engineering design construction from now on, introduces and ram Heavy ratio, defines and calculates the heavy ratio of rammer, and converting for the usefulness of hammer ram during strong rammer provides a kind of new method, it is possible to ram when evaluating strong rammer Hammer energy conversion efficiency, is rammed by scene examination, can obtain the heavy ratio of rammer and the curve thereof of corresponding hammer ram, be conducive to selecting higher turn Change the strong rammer equipment of usefulness.

Summary of the invention

The present invention overcomes the deficiency that prior art exists, technical problem to be solved to be to provide a kind of heavy ratio of definition rammer, and to ram Hammering into shape is object of study, calculates the method rammed heavy ratio and evaluate tamping efficiency, to raising efficiency in Practical Project, energy distribution, fall Low power consuming is significant.

In order to solve above-mentioned technical problem, the technical solution adopted in the present invention is: defines and calculates the heavy ratio of rammer and evaluate hammer ram conversion The method of usefulness, by the test of ramming of many group hammer rams, definition also calculates each group of heavy ratio of rammer respectivelyDraw ramming times Ramming heavy combination than curve chart to contrast to evaluate the conversion usefulness of hammer ram, wherein b clicks ramming volume for measuring gained, and S is for passing through The hammer ram travel values that integrating meter calculates, specifically comprises the following steps that

A) it is respectively mounted acceleration transducer in the top center often organizing hammer ram and carries out ramming test, and remembered by dynamic test Acquisition Instrument The dynamic acceleration data of the every blow of hammer ram are often organized in record；

B) acceleration-time curve of the often group every blow of hammer ram is drawn according to the dynamic acceleration data gathered；

C) the time zero at the flex point changed by acceleration in the above-mentioned acceleration-time curve often organizing hammer ram, as hammer ram The starting point of impact stroke, the acceleration-time curve of the lower hammer ram impact stroke of effect of clicking after being revised；

D) land speed as initial condition with hammer ram, as the beginning of impact time-histories, the acceleration-time curve collected is passed through A/D is converted to discrete data；

E) according to shock dynamics principle, by above-mentioned acceleration information with numerical integration

$v_i=v_0-\underset{i=1}{\overset{n}{\Σ}}\left(\right|a_i|\·\mathrm{\δ}t)$

WhereinLanding speed for hammer ram, h is falling distance of rammer, and g is acceleration of gravity；

a_iFor acceleration transducer test value, δ t is time integral step-length；

Calculate ram speed v often organized_i, often organized the speed time-history curves of hammer ram；

F) further by speed data with numerical integration

$S_i=\underset{i=0}{\overset{n}{\Σ}}({\mathrm{\ν}}_i\·\mathrm{\δ}t)$

Wherein v_iFor above-mentioned ram speed, δ t is time integral step-length；

Calculate often group hammer ram travel values S, obtain the displacement time-history curves of this group hammer ram；

G) measure the crater depth after the often group every blow of hammer ram by level gauge, draw and click ramming volume b；

H) click ramming volume b and above-mentioned numerical integration gained hammer ram travel values S by what above-mentioned measurement drew, calculate each group of rammer The rammer hammering every blow into shape is heavy than λ:

$\mathrm{\λ}=\frac{b}{S}$

According to the heavy numerical value than λ of multiple rammers, show that ramming times rams to sink and compare curve；

I) ramming times organizing hammer ram rams heavy being integrated on a curve chart than curve more to contrast, curve above Corresponding hammer ram corresponding conversion usefulness in impact stroke is high.

Acceleration transducer in described step a) is piezoelectric acceleration transducer.

Described c) step starts to organize the revised acceleration-time curve of hammer ram more and is integrated into a curve chart and contrasts Observe and analyze.

The present invention compared with the existing technology has the advantages that.

1, the ratio of every blow actual measurement ramming volume b and hammer ram impact stroke value of calculation S is defined as ramming heavy ratio λ by the present invention, is rammed Hit number of times and ram heavy ratio curve, cross and many group hammer ram gained ramming times are rammed heavy ratio curve comparison analysis, it is achieved strong rammer usefulness, The quantitative assessment of consolidation effect, for design optimization and the strong rammer lectotype selection offer reference of basement process, method is simple, and physics is anticipated Justice clearly, calculates the most convenient economy.

2, the present invention is with hammer ram as object of study, compensate for the soil body as object of study, relies in ground and buries underground such as soil pressure cell Etc. determining this problem fragile of testing element in several methods of ramming, economical and practical.

Accompanying drawing explanation

The invention will be further described below in conjunction with the accompanying drawings.

Fig. 1 is that A group the 5th hits omnidistance acceleration-time curve.

Fig. 2 is that B group the 5th hits omnidistance acceleration-time curve.

Fig. 3 is A, B group acceleration initial time zero time-history curves.

Fig. 4 is A, B group speed time-history curves.

Fig. 5 is A, B group hammer ram displacement time-history curves.

Fig. 6 is that A, B group hammer ram ramming times rammer is heavy compares curve.

Detailed description of the invention

The present invention defines and calculates and rams the method sunk than evaluating hammer ram conversion usefulness, and by the tests of ramming organizing hammer rams, definition is also more Calculate each group respectively and ram heavy ratioDraw heavy the combination than curve chart of ramming times rammer to contrast to evaluate the conversion usefulness of hammer ram, Wherein b is for measuring gained ramming volume, and S is the hammer ram travel values calculated by integrating meter, specifically comprises the following steps that

A) it is respectively mounted acceleration transducer in the top center often organizing hammer ram and carries out ramming test, and remembered by dynamic test Acquisition Instrument The dynamic acceleration data of the every blow of hammer ram are often organized in record；

B) acceleration-time curve of the often group every blow of hammer ram is drawn according to the dynamic acceleration data gathered；

C) the time zero at the flex point changed by acceleration in the above-mentioned acceleration-time curve often organizing hammer ram, as hammer ram The starting point of impact stroke, the acceleration-time curve of the lower hammer ram impact stroke of effect of clicking after being revised；

D) land speed as initial condition with hammer ram, as the beginning of impact time-histories, the acceleration-time curve collected is passed through A/D is converted to discrete data；

E) according to shock dynamics principle, by above-mentioned acceleration information with numerical integration

$v_i=v_0-\underset{i=1}{\overset{n}{\Σ}}\left(\right|a_i|\·\mathrm{\δ}t)$

WhereinLanding speed for hammer ram, h is falling distance of rammer, and g is acceleration of gravity；

a_iFor acceleration transducer test value, δ t is time integral step-length；

Calculate ram speed v often organized_i, often organized the speed time-history curves of hammer ram；

F) further by speed data with numerical integration

$S_i=\underset{i=0}{\overset{n}{\Σ}}({\mathrm{\ν}}_i\·\mathrm{\δ}t)$

Wherein v_iFor above-mentioned ram speed, δ t is time integral step-length；

Calculate often group hammer ram travel values S, obtain the displacement time-history curves of this group hammer ram；

G) measure the crater depth after the often group every blow of hammer ram by level gauge, draw and click ramming volume b；

H) click ramming volume b and above-mentioned numerical integration gained hammer ram travel values S by what above-mentioned measurement drew, calculate each group of rammer The rammer hammering every blow into shape is heavy than λ:

$\mathrm{\λ}=\frac{b}{S}$

According to the heavy numerical value than λ of multiple rammers, show that ramming times rams to sink and compare curve；

I) ramming times organizing hammer ram rams heavy being integrated on a curve chart than curve more to contrast, curve above Corresponding hammer ram corresponding conversion usefulness in impact stroke is high.

Acceleration transducer in described step a) is piezoelectric acceleration transducer.

Described c) step starts to organize the revised acceleration-time curve of hammer ram more and is integrated into a curve chart and contrasts Observe and analyze.

Embodiment

A) with the hammer ram of two a diameter of 32cm of ferrous materials as object of study, two groups of tests are carried out.A group quality is 39.2kg, Falling away from for 2.5m, energy level is 980N.m；B group hammering quality is 70kg, falls away from for 1.4m, and energy level is identical is also 980N.m. Foundation material selects water content loess-like silt near optimum moisture content 14% to fill, and filling-up thickness 0.75m fills Degree of compaction 0.85, planar dimension 4m × 3m, often group test rams 14 times.Undercarriage and automatically-unhooked be easy device. For obtaining hammer ram acceleration-time curve in impact process, arranging piezoelectric acceleration transducer at hammer ram top, model is DH131E, utilizes DH5956 dynamic strain indicator to carry out the collection of dynamic acceleration signal.Crater depth uses level gauge to carry out Measure with the ramming volume obtaining every blow.To the hammer ram accelerating curve collected after test, often hit ramming volume and study, this Embodiment takes the representational 5th and hits data computational analysis.

B) the main time-history curves of A group is drawn as it is shown in figure 1, the main time-history curves of B group according to the dynamic acceleration data gathered As in figure 2 it is shown, abscissa i.e. time shaft, unit is s；Longitudinal axis numerical value is that negative value represents acceleration direction upwards, and unit is m/s²。

C) according to the characteristic of piezoelectric acceleration transducer, no matter hammer ram is at the uniform velocity lifting by crane, and freely falling body before still contacting to earth all is located In inertial states, the data theory that instrument shows is zero, as shown in Figure 1, Figure 2 in point 1 before the acceleration value base of the longitudinal axis This is in zero-bit.When point 1 post-acceleration starts to occur significant change, represent that hammer ram receives other active force in addition to gravity.Cause This, will put the starting point of the hammer ram impact stroke discussed at 1 as plan.

Respectively using index point in Fig. 1, Fig. 21 as the time zero of time-history curves, time point at change will be started by acceleration Zero, the lower acceleration-time curve revised of effect of can clicking is as it is shown on figure 3, namely to click lower A, B group hammer ram main Impact stroke.

D) speed is landed as initial condition with hammer ram, as the beginning of impact time-histories, Acceleration time course A, B group collected Curve negotiating A/D is converted to discrete data；

E) generally, the air drag being subject to during hammer ram freely falling body is compared its weight and can be ignored.Therefore, hammer ram The initial velocity that lands can draw as the following formula:

A group:

${\mathrm{\ν}}_A=\sqrt{2gh}=\sqrt{2\×9.8\×2.5}=7m/s$

B group:

${\mathrm{\ν}}_B=\sqrt{2gh}=\sqrt{2\×9.8\×1.4}=5.24m/s$

Using two groups land initial velocity as initial condition (ignoring the crater depth of 0.1～0.2m to landing the impact of speed), can Obtain ram speed calculating formula, it may be assumed that

$v=v_0-{\∫}_0^t\left|a\right|dt$

Wherein a is acceleration transducer test value, v₀Initial velocity (the most above-mentioned v is landed for hammer ram_A、v_B)；

Above-mentioned calculating formula is converted to numerical integration form:

$v_i=v_0-\underset{i=1}{\overset{n}{\Σ}}\left(\right|a_i|\·\mathrm{\δ}t)$

Wherein a_iFor acceleration transducer test value, δ t is time integral step-length；

For the acceleration-time curve of A, B group shown in Fig. 3, program according to this numerical integration, calculate two respectively Group ram speed v, obtains speed time-history curves as shown in Figure 4.

When being f) zero with time coordinate in Fig. 4, the displacement S of hammer ram₀=0, as initial condition, can obtain the position of hammer ram impact stroke Shifting calculating formula:

$S=S_0+{\∫}_0^t{S}^{\′}={\∫}_0^t\mathrm{\ν}dt$

This calculating formula is converted to numerical integration form:

$S_i=\underset{i=0}{\overset{n}{\Σ}}({\mathrm{\ν}}_i\·\mathrm{\δ}t)$

Wherein S_iFor hammer ram displacement, v_iFor the velocity amplitude of hammer ram, δ t is time integral step-length；

Two groups of rate curves of A, B are calculated according to this numerical integration, obtains the displacement time-history curves of hammer ram impact stroke such as Shown in Fig. 5.Wherein, A group hammer ram stroke S_A=0.067m, B group hammer ram stroke S_B=0.0926m.

G) measure, by level gauge, the ramming volume b that A group hammer ram the 5th hits_A=0.0072m, b_B=0.015m.

H) the ramming volume b drawn by above-mentioned measurement and above-mentioned numerical integration gained hammer ram travel values S, calculated A, B group and ram Hammer the 5th rammer hit into shape heavy than λ:

$\mathrm{\λ}=\frac{b}{S}$

:

Repeat b)～h) step, obtain the heavy numerical value than λ of multiple rammer, and it is heavy than curve such as Fig. 6 institute to show that ramming times rams Show.

I) to ram heavy ratio λ evaluation hammer ram conversion usefulness, A, B group hammer ram is calculated by said method and draws the rammer often organizing hammer ram Hit number of times and ram heavy ratio curve, contrast heavy for the ramming times rammer of two groups of hammer rams than curve, as shown in Figure 6, B suite Line is positioned at above A suite line, illustrates that in B group hammer ram impact stroke, corresponding conversion usefulness is high, should select B group when constructing Strong rammer equipment.

It is in impact stroke that rammer sinks than λ measurement, the ratio of the ramming volume that hammer ram impact ground generation plastic deformation is corresponding, actual On indirectly reflect the ability that strong rammer energy is converted to the plastic deformation ability of the soil body, reflect the impact usefulness often hit, i.e. strong rammer effect Rate.Ram heavy than be Different Weight, shape, fall away from hammer ram impact the result of corresponding ground, ram heavy than and curve both by this The impact of a little factors, is also the concentrated expression of these factors simultaneously.Therefore, ram heavy ratio and can evaluate and compare hammer ram conversion usefulness, The most not only science, accurately, convenient, but also economical, Practical Project is had great importance.

Claims (3)

1. definition calculating ram heavy than the method evaluating hammer ram conversion usefulness, it is characterised in that ram test by many group hammer rams, Definition also calculates each group of heavy ratio of rammer respectivelyDrafting ramming times rams heavy than curve chart combination contrast turning with evaluation hammer ram Changing usefulness, wherein b clicks ramming volume for measuring gained, and S is the hammer ram travel values calculated by integrating meter, and concrete steps are such as Under:

A) it is respectively mounted acceleration transducer in the top center often organizing hammer ram and carries out ramming test, and remembered by dynamic test Acquisition Instrument The dynamic acceleration data of the every blow of hammer ram are often organized in record；

B) acceleration-time curve of the often group every blow of hammer ram is drawn according to the dynamic acceleration data gathered；

C) the time zero at the flex point changed by acceleration in the above-mentioned acceleration-time curve often organizing hammer ram, as hammer ram The starting point of impact stroke, the acceleration-time curve of the lower hammer ram impact stroke of effect of clicking after being revised；

D) land speed as initial condition with hammer ram, as the beginning of impact time-histories, the acceleration-time curve collected is passed through A/D is converted to discrete data；

E) according to shock dynamics principle, by above-mentioned acceleration information with numerical integration

$v_i=v_0-\underset{i=1}{\overset{n}{\Σ}}\left(\right|a_i|\·\mathrm{\δ}t)$

WhereinLanding speed for hammer ram, h is falling distance of rammer, and g is acceleration of gravity；

a_iFor acceleration transducer test value, δ t is time integral step-length；

Calculate ram speed v often organized_i, often organized the speed time-history curves of hammer ram；

F) further by speed data with numerical integration

$S_i=\underset{i=0}{\overset{n}{\Σ}}(v_i\·\mathrm{\δ}t)$

Wherein v_iFor above-mentioned ram speed, δ t is time integral step-length；

Calculate often group hammer ram travel values S, obtain the displacement time-history curves of this group hammer ram；

G) measure the crater depth after the often group every blow of hammer ram by level gauge, draw and click ramming volume b；

H) click ramming volume b and above-mentioned numerical integration gained hammer ram travel values S by what above-mentioned measurement drew, calculate each group of rammer The rammer hammering every blow into shape is heavy than λ:

$\mathrm{\λ}=\frac{b}{S}$

According to the heavy numerical value than λ of multiple rammers, show that ramming times rams to sink and compare curve；

I) ramming times organizing hammer ram rams heavy being integrated on a curve chart than curve more to contrast, curve above Corresponding hammer ram corresponding conversion usefulness in impact stroke is high.

Definition the most according to claim 1 also calculates the method ramming heavy ratio evaluation hammer ram conversion usefulness, it is characterised in that: institute Stating the acceleration transducer in step a) is piezoelectric acceleration transducer.

Definition the most according to claim 1 and 2 also calculates the method ramming heavy ratio evaluation hammer ram conversion usefulness, it is characterised in that: Described c) step starts to organize the revised acceleration-time curve of hammer ram more and is integrated into a curve chart and carries out paired observation And analyze.