CN1237668A - Blast-tamping method for compacting underwater sand foundation - Google Patents

Abstract

The present invention relates to an explosion tampering method for compacting underwater dumped sand foundation. Said method includes the following steps: firstly desilting in the position of underwater foundation, dumping and filling underwater sand foundation, distributing powder bags on the surface of sand foundation in the mode of network form and detonating these powder bags. Said invention also provides a formula for calculating the radius of effective action range of every powder bag, and possesses the obvious advantages of good construction quality and rapid construction speed, etc..

Description

Encrypt the blast-tamping method of ramming bedding under water

The invention belongs to the underwater explosion engineering, ground is encrypted engineering, is meant especially and encrypts the blast-tamping method of ramming bedding under water.

The closely knit vibroflotation method that always adopts at home of ramming bedding under water, it needs special-purpose main equipment, long-time operation at sea, construction speed is slow.Countries such as the former Soviet Union encrypt in the engineering at some soil and have adopted the closely knit technology of quick-fried rammer, find out that according to relevant document closely knit employed dose of sand base is very big for it under water, and closely knit thickness is less, there is tangible Technological Economy defective, is not suitable for China's engineering construction fully and adopts.In order to improve the closely knit conventional method of sand base, domestic how tame unit has carried out the theoretical research and the Application and Development work of blast close sand base, but obtained achievement does not have tangible progress yet than countries such as the former Soviet Unions on technical-economic index, in all can't being applied to build, cause vibroflotation method close sand base to be still the unique method of the close sand base of not replacing at home.

Vibroflotation method is because of the equipment complexity, and speed of application is slow, has restricted the progress and the duration of engineering construction, and techno-economic question such as the external quick-fried rammer technology that oneself has is big because of explosive consumption, complex process and be not suitable for domestic employing.

The objective of the invention is to, a kind of encryption blast-tamping method of ramming bedding under water is provided, it is in order to boost productivity, traditional handicraft to be carried out new technology transformation and innovation, exploring the economic saving of a cover, fast, the measured sand base of the matter densification process of speed.

The present invention encrypts the blast-tamping method of ramming bedding under water, its implementation is: bedding position desilting at first under water, throw the back-up sand base under water, after sand base that throwing is filled out reaches certain drilling depth and elevation, at the latticed layout blasting charge of sand primary surface, and ignite above-mentioned cartridge bag, the weight effective range radius of single cartridge bag should be followed following formula and calculate $R={\left(\frac{3\mathrm{\α}{Q}_{c}Q}{4\mathrm{\π}(P_0+\mathrm{\γgD})}\right)}^{\frac{1}{3}}$

The pass apart from a, b and single cartridge bag effective range radius R that can estimate the cartridge bag of latticed layout in view of the above is

a≌2R,b≌2R

After the weight of single cartridge bag was determined, the pass of its quick-fried rammer was then calculated by following formula $N=K\frac{\mathrm{abH}}{Q}$

Be the closely knit effect of prediction blast, can by following formula estimate quick-fried rammer finish after the increment of sand base compactness $\mathrm{\Δ}{D}_r=4\left({3+10K}^{\frac{1}{3}}\right)e^{-0.06D_r}$

The blast of soil is closely knit to be to be that the dynamic load active forces such as shock wave that medium is propagated explosive charge are finished with wherein pore water.Soil is loose more, and hole therebetween is just big more, the easy more relative motion that causes soil skeleton of blast wave, and it is closely knit preferably that soil is obtained.Soil obtains closely knit complexity, and also big flood and the grating with its particle is relevant, it is easier with big particle diameter to be that the piece stone ground of representative is encrypted with respect to the sandy ground base blast of tiny particle diameter, grating is better because the former is general, under the disturbance of detonation power, smaller piece stone is easier to be extruded pore water and fills up hole, and latter's hole is less, and pore water difficulty is extruded and obtains closely knit.This just explains that to the difficult closely knit a kind of image of sand base its real process is so that liquefaction---fixed is feature.

Be the effect further specify feature of the present invention and to be reached, the present invention is further illustrated below in conjunction with accompanying drawing and embodiment, wherein:

Fig. 1 is the present invention's bedding sectional schematic diagram under water, shows the position of sand base and cartridge bag.

Fig. 2 is a unit of the present invention cloth medicine grid schematic diagram, the relative distance of display unit cartridge bag.

The sectional drawing of bedding under water as shown in Figure 1, wherein, 1 is that cartridge bag, 2 is that mud, 3 is the sand base; Among Fig. 2,4 is the cartridge bag effective range. The present invention at first is under water bedding position desilting, throws under water The back-up sand base is after the sand base of throwing reaches certain drilling depth and elevation, at the latticed layout explosive of sand primary surface Bag, and ignite above-mentioned cartridge bag. After the cartridge bag blast, impact under water and involve under the strong Under Dynamic Load of foundation vibration, Saturated sand liquefies immediately, the relative motion that this has accelerated the discharge of pore water and has caused simultaneously sand grains, warp Cross the sand grains structural rearrangement, hole is wherein reduced, reach more closely knit state after fixed. It is closely knit to explode Effect is the most relevant with the original state of sand base, and through laboratory test, formula (1) has provided sand base warp The relation of raising relative density initial with it of blast relative density, the closely knit effect of measurable blast accordingly, For engineering construction provides reference.

Know according to the underwater explosion theory, will generate gas under water by the explosion gas product at the cartridge bag place behind the explosive charge Bubble is also upwards propagated, it is considered herein that maximum radius that bubble expands for the first time be the blasting charge to sand body effectively The sphere of action radius can determine the explosive arrangement in the practice of construction thus. Formula (2) has provided fried The computational methods of the effective range radius that produces after the medicine blast, practice of construction Chinese medicine infantees is set to square net Lattice are because generally bedding is very long and width is narrower under water, so cloth medicine and detonating all along bedding length direction order Carry out, most typical cloth prescription unit grid as shown in Figure 2, wherein cartridge bag array pitch and spacing by formula (3) Approximate calculation.

Know that from laboratory test repeatedly explode effect to the packing of sand body of little dose has positive cumulative Effect, the explosive of the equivalent weight of namely exploding, the whole doses of the cumulative effects of blast once explode several times Effective, according to environmental selection after the single maximum single cartridge bag weight of detonating, the sand base reaches engineering and establishes The required quick-fried rammer pass of meter packing is (4) estimation by formula. $\mathrm{\Δ}{D}_r=4(3+10K^{\frac{1}{3}})e^{-0.06D_r}---\left(1\right)$ $R={\left(\frac{3\mathrm{\α}{Q}_{c}Q}{4\mathrm{\π}(P_0+\mathrm{\γgD})}\right)}^{\frac{1}{3}}---\left(2\right)$

           a≌2R,b≌2R                         (3) $N=K\frac{\mathrm{abH}}{Q}---\left(4\right)$ Wherein:

D _r---the initial relative density of sand base, %;

Δ Dr---sand base relative density increment behind the quick-fried rammer, %;

E---index, 2.178;

K---correction factor, 0.05～0.1kg/m³；

H---sand base thickness, m;

D---the bedding depth of water, m;

Q---single cartridge bag weight, 0.5～20kg is generally determined by the Environmental security situation;

The single weight effective range radius of R---cartridge bag, m;

A, b---the array pitch and the charges interval of cartridge bag when being respectively blasting charge layout, m;

N---sand base reaches the required quick-fried rammer pass of dense state, adjusts relevant parameter and is taken as integer;

Q _c---explosive specific heat, for TNT, 4.18 * 10 ⁶J;

α---explosive bubble energy utilization factor, 0.35～0.5;

γ---water proportion, kg/m ³

G---acceleration of gravity, 9.8m/s ²

P ₀---normal atmosphere power, 101325N/m ²

Quick-fried rammer close sand based method according to underwater explosion theory and the closely knit result of the test invention of laboratory sand base is applicable to complex environment, and the more mechanical vibroflotation method of its technical-economic index has remarkable advantages, has realized the purpose of invention fully.With respect to vibroflotation method and external quick-fried rammer method close sand base, quick-fried rammer close sand based method has following characteristics and effect:

(1), equipment and technology are simple

Blast-tamping method need not the special purpose ship machine equipment, and the operation at sea time is short, and is simple to operate, is subjected to ectocine little.

(2), quality is good, speed is fast

The transient state of explosive charge is finished the ripple contain factor of the bubble that characteristic and explosion product form in water, blast-tamping method is had fast and the action characteristic that repeats to load, and this impels the process of sand base fluidization, discharging consolidation to accelerate, and closely knit quality is improved.Generally speaking, the time of blast-tamping method construction only be vibrocompaction ～

Sand base solidity ratio vibroflotation method improves mark and passes through and hit several 3～5 and hit.

(3), the economic saving

Quick-fried rammer close sand based method economy is saved and is shown 2 aspects, and first engineering cost is low, and direct effect is to reduce construction costs; It two is to save the duration, by shortening the closely knit engineering time of sand base greatly, can save the cost of whole engineering construction indirectly in a large number.

(4), degree of safety height

Blast-tamping method is compared with external quick-fried rammer method, greatly reduce the use amount of explosive, and the ramming bedding under the closely knit equal environment, the used explosive charge of blast-tamping method have only foreign technology

, this not only makes blast-tamping method reduce labour intensity, and has reduced the harm of foundation vibration and underwater blast wave greatly, has improved safety of construction, makes blast-tamping method can be widely used in very easily applying in the complex environment.

Embodiment 1:

As the long 214m of ramming bedding, the thick H=5.3m of ramming, depth of water D=14m, the about D of the initial relative density of ramming bedding _r=20%, mark passes through and hits several 5～7 when hitting, and designing requirement ramming compactness reaches 15 and hits mark and pass through and hit number.Choose Q=2kg according to the site safety situation, K=0.08kg/m ³, a=0.05, Q _c=4.18 * 10 ⁶J calculates according to (2) (3) (4) formula, determines that the quick-fried rammer parameter of this harbour is as follows: Q=2.0kg, a=3.3m, b=3.0m, N=2.Pass through through 2 times laggard rowers of quick-fried rammer according to this parameter and to hit several quality inspections, prove all to reach the compactness requirement.By statistics, 90% passes through clicks 〉=18 with subscript hits, and average mark passes through and hits number is 23 to hit, considerably beyond design standard.

Also can do a rough estimate according to formula (1) to the variation of each quick-fried rammer relative density, if the initial relative density of sand bedding is 20%, after then calculating the quick-fried rammer of first pass by formula (1), the relative density increment is 9%, and this makes sand body reach 29% relative density, then behind second time quick-fried rammer, relative density increment 5%, sand body reach 34% relative density, and this has made sand body reach comparatively dense state, carry out the 3rd time quick-fried rammer again and estimate to increase about 4% relative density, unnecessary.Because relative density is difficult the measurement in engineering is used, thus the general situation of not judging sand base compactness with this index, and adopt mark to pass through several methods of hitting.

Embodiment 2:

As the long 90m of a segment base bed, bedding ramming thickness H=13.30m, depth of water D=15m, ramming bedding initial phase is to density D _r=20%, mark passes through and hits several 5～7 when hitting, and designing requirement ramming compactness reaches 15 and hits mark and pass through and hit number.Choose Q=6.0kg according to field condition, K=0.08kg/m ³, a=0.5, Q _c=4.18 * 10 ⁶J calculates according to formula (2), (3), (4), determines that the quick-fried rammer parameter of this harbour is as follows: Q=6.0kg, a=4.0m, b=3.3m, N=2.Pass through through 2 times laggard rowers of quick-fried rammer according to determined parameter and to hit several quality inspections, prove all to reach the compactness requirement.By statistics, 90% passes through clicks 〉=18 with subscript hits, and average mark passes through and hits number is 21 to hit, considerably beyond design standard.

Claims (4)

1, a kind of encryption blast-tamping method of ramming bedding under water, the back-up sand base is thrown in bedding position desilting at first under water under water, after sand base that throwing is filled out reaches certain drilling depth and elevation, at the latticed layout blasting charge of sand primary surface, and ignites above-mentioned cartridge bag, it is characterized in that,

The single weight effective range radius of cartridge bag should be followed following formula and calculate $R={\left(\frac{3\mathrm{\α}{Q}_{c}Q}{4\mathrm{\π}(P_0+\mathrm{\γgD})}\right)}^{\frac{1}{3}}$

Wherein: D is the bedding depth of water, m; Q is single cartridge bag weight, 0.5～20kg; R is the single weight effective range radius of cartridge bag, m; Q _cFor explosive specific heat, for TNT, 4.18 * 10 ⁶J; α is an explosive bubble energy utilization factor, 0.35～0.5; G is an acceleration of gravity, 9.8m/s ²P ₀Be normal atmosphere power, 101325N/m ²γ is a water proportion, kg/m ³

2, press the described a kind of encryption of claim 1 blast-tamping method of ramming bedding under water, it is characterized in that the pass apart from a, b and single cartridge bag effective range radius R of the blasting charge of latticed layout is a ≌ 2R, b ≌ 2R; Wherein: the array pitch and the charges interval of cartridge bag when a, b are respectively blasting charge layout, m.

3, press the described a kind of encryption of claim 1 blast-tamping method of ramming bedding under water, it is characterized in that, after the weight of single cartridge bag was determined, the pass of its quick-fried rammer was then calculated by following formula $N=K\frac{\mathrm{abH}}{Q}$

Wherein: N reaches the required quick-fried rammer pass of dense state for the sand base; K is a correction factor, 0.05～0.1kg/m ³H is a sand base thickness, m.

4, press the described a kind of encryption of claim 1 blast-tamping method of ramming bedding under water, it is characterized in that, for the effect that the prediction blast is closely knit can be by following formula estimation $\mathrm{\Δ}{D}_r=4(3+10K^{\frac{1}{3}})e^{-0.06D_r}$

Wherein: Δ Dr is a quick-fried rammer back sand base relative density increment, %; D _rBe the initial relative density of sand base, %; E is an index, 2.178.

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