CN101314967B - Indoor vibration isolation method for existent buildings at subway operation section - Google Patents

Abstract

The invention discloses an indoor vibration isolation method for the existing building in a subway operating area. The method proposes an indoor ground vibration isolation system of a building, and a geometric specification and a dynamic parameter of a vibration isolator based on the principle of structural dynamics and according to the characteristics of indoor ground vibration. The vibration isolation system is made of three structural layers: a vibration isolator core layer composed of a rubber vibration isolator is arranged at the bottom part; a C20 plain concrete layer is arranged at the middle part; and a common indoor ground is arranged at the top part. The vibration isolator adopts a high-strength metallic film layer (lapped layer) to be artificially synthesized into special compounded rubber, and the static stiffness of the rubber is determined by the indoor dynamic load, the number of the vibration isolator, and the ground subsidence controlling displacement. The indoor vibration isolation method has the advantages that the vibration isolation effect is good, and the vibration isolation efficiency is generally above 80 percent.

Description

Indoor vibration isolation method for existent buildings at subway operation section

Technical field

The present invention relates to a kind of building indoor vibration isolation method, the indoor vibration in existing house that especially subway is caused has significant isolation effect.

Background technology

At present commonly used mainly is that the ripple barrier is set for the City Rail Transit System vibration isolation means of subway vibration particularly, specifically comprises: the excavation gutter, the wave resistance piece is set and strengthens the rigidity of soil.These measures all are that total and vibration source are separated, and comparatively are suitable for new building.For existing building, particularly when building be positioned at population and building is intensive, during the urban community of the suitable moulding of development & construction, these measures are difficult to carry out.For construction time building more of a specified duration, through the reinforcing of integrated structure, improve the integral rigidity of structure, can play certain damping effect.But make indoor vibration further be reduced to the acceptable degree of people, also need carry out indoor vibration isolation at last.

Summary of the invention

The object of the present invention is to provide a kind of indoor vibration isolation method for existent buildings at subway operation section, be used to isolate the flooring vibration in the existing house that subway causes, make it to be reduced to the acceptable level of human body.

For reaching above purpose, the solution that the present invention adopted is:

A kind of existent buildings at subway operation section indoor vibration isolation technology; Based on the structural dynamics principle; According to the flooring vibration performance and the building structure characteristics in house, the balance of taking all factors into consideration flooring and building structure is set up the method for easy, practical estimation vibrating isolation system vibration isolation efficiency with stable; Research and propose following vibration isolation technology and relevant art parameter: the integral body excavation is carried out on each ground, room of existing building bottom; Cutting depth >=200mm, tamped backfill then, supremely the end of from the native face of compacting do three decks:

(1) bottom.For the vibration isolation core layer, constitute by rubber shock absorber, vibration isolator should adopt the artificial synthetic extraordinary compounded rubber of high duty metal thin layer (lamination), the quiet stiffness K of rubber _ZsCalculate by the formula (2) that proposes, rubber height>=30mm, its bottom surface>=150mm * 150mm, the quantity of vibration isolator is looked concrete engineering with the laying spacing and is decided, and suggestion vibration isolator spacing is≤500mm.Core layer whole height >=35mm.

$\frac{W_I}{N}\frac{1}{K_{\mathrm{zs}}}<\mathrm{\&rho;}\left(\mathrm{mm}\right)---\left(1\right)$

In the following formula, W _I, N, ρ is respectively indoor dynamic load, vibration isolator number and Land-Subsidence Control displacement.

(2) intermediate layer.Be C20 plain concrete layer, thickness >=100mm.

(3) top layer.Be general room ground, the construction of this layer will be carried out after 24 hours pouring the intermediate layer.

Fill with polymeric foam boards in space between three decks.In addition, each room has an independently vibration isolation system of one's own, is made up of jointly floorboard and one group of vibration isolator.Main theoretical basis of the reform of Chinese economic structure of the present invention is following:

Structure of vibration isolation is through reducing the frequency of the vibrating isolation system that vibration isolator and structure constitute, thereby the reduction structure is to the reaction of the inputted vibration that is higher than (comprise and equaling) this frequency.The relation of vibrating isolation system vibration frequency and mass of system does

$f_n=\frac{1}{2\mathrm{\&pi;}}\sqrt{\frac{K_z}{M}}---\left(2\right)$

It is the strongest that the indoor vibration of multistoried building is generally bottom, and the object of indoor vibration isolation also mainly is this floor.It is daily stable that the building flooring must keep, and promptly requires vibrating isolation system should possess suitable rigidity.Visible by formula (2), frequency one timing, rigidity is big, and then the quality of system is also big.At structure level area one regularly, system's vertical height is by its quality decision.For existing building, in general superstructure has become the integral body that can not change with the basis.The heavy burden that be to keep the globality of structure and do not increase the basis, indoor to supply with the spatial altitude that vibration isolation handles just very limited.In addition, for the balance that keeps the flooring with stable, generally need to make up the vibrating isolation system of forming by a plurality of vibration isolators.And the number of the fair and vibration isolator of vibrating isolation system is mutually direct ratio, and this has just further aggravated the restriction of structure space to the configuration of vibrating isolation system quality.Because the horizontal vibration that the pedestrian walks about and subway causes, the existing building indoor vibration isolation is different from the vibration isolation to other place, also is the lateral stability and the requirement of vertical stability property of earth construction high.

The house earth surface vibrating isolation system that makes up is a single-degree-of-freedom system, and its main characteristic parameters has: system free vibration frequency, quiet rigidity and quality.These Determination of Parameters will be taken all factors into consideration power performance, the design feature of extraneous vibration characteristic, vibration isolation material.The key kinetic parameter of vibrating isolation system vibration isolating effect is the natural frequency of system.If the frequency of the vertical inputted vibration of house earth surface that City Rail Transit System causes is f _a, f _nBe the intrinsic frequency of vibrating isolation system vertical motion, if both satisfy

$f_a/f_n\&GreaterEqual;\sqrt{2}---\left(3\right)$

Then this system to frequency f greater than (comprise and equaling) f _aInputted vibration the vibration isolation effect is all arranged, generally speaking

$5\&GreaterEqual;f_a/f_n\&GreaterEqual;\sqrt{2}---\left(4\right)$

Vibration isolation coefficient η does

$\mathrm{\&eta;}=\sqrt{\frac{1+{4\mathrm{\&xi;}}^2\frac{f^2}{f_n^2}}{{(1-\frac{f^2}{f_n^2})}^2+{4\mathrm{\&xi;}}^2\frac{f^2}{f_n^2}}}---\left(5\right)$

F＞f in the formula _α, ξ is the vibrating isolation system damping ratio, gets 0.1.Vibration isolation efficiency T does

T＝(1-η)×100％ (6)

The lower limiting frequency of the third-octave at peak acceleration level place is designed isolation frequency as vibrating isolation system, confirmed the kinetic parameter that vibrating isolation system is concrete.The method of basis with the corresponding vibration isolation coefficient estimate of the lower limiting frequency vibrating isolation system vibration isolation efficiency of the third-octave at peak acceleration level place proposed.The AL Acceleration Level that a certain third-octave centre frequency is corresponding is the equalization result of each frequency accelerating stage in this sound interval.f _αGet the lower limiting frequency of the sound interval at peak acceleration level place.

With f _αCorresponding vibration isolation coefficient η _aWith vibration isolation efficiency T _aBe respectively

${\mathrm{\&eta;}}_a=\sqrt{\frac{1+{4\mathrm{\&xi;}}^2\frac{f_a^2}{f_n^2}}{{(1-\frac{f_a^2}{f_n^2})}^2+{4\mathrm{\&xi;}}^2\frac{f_a^2}{f_n^2}}}---\left(7\right)$

T _a＝(1-η _a)×100％ (8)

Obviously have

η＜η _a T _a＜T (9)

Can know by formula (5) and formula (6), with the corresponding vibration isolation coefficient of vibrating isolation system third-octave centre frequency η ₀With vibration isolation efficiency T ₀Also have

η ₀＜η _a T ₀＞T _a (10)

And, through the third-octave peak acceleration level L on the ground after the vibration isolation processing _{α 0}

L _a0＜99η ₀ (11)

Through a large amount of example calculation, this kind method has good vibration isolating effect, and vibration isolation efficiency is generally more than 80%.

Owing to adopted such scheme, the present invention to have following characteristics: adopt this method can obtain good vibration isolating effect, vibration isolation efficiency is generally more than 80%.In addition, this method cost is low, and making, installation and easy construction are convenient in engineering, apply.

Description of drawings

Fig. 1 is the vibrating isolation system vibration isolator layout plan of the embodiment of the invention.

Fig. 2 is the vibrating isolation system vertical section constructional drawing of the embodiment of the invention.

Fig. 3 is the vibrating isolation system cross section constructional drawing of the embodiment of the invention.

1. rubber shock absorbers among the figure, 2.C20 plain concrete layer, 3. general room ground, 4. polymeric foam boards

The specific embodiment

Below in conjunction with the accompanying drawing illustrated embodiment the present invention is further described.

Like Fig. 1, five layers of brick mix structure shown in 2,3, subway tunnel passes under building, and this building is in light weight, and structural integrity is poor, and the construction age is of a specified duration, so under extraneous vibration, can produce stronger reaction.The third-octave analysis that this house vertical motion is carried out shows that the centre frequency of this house peak acceleration level is positioned at 80Hz, and maximum vibration is 99dB.f _αGet the shake lower limiting frequency of sound interval at level place of peak acceleration.Here, f _αGet 70.7107, can get according to formula (4)

50≥f _n≥14.1421 (12)

1) mass of system M and vibration isolator height H.

Analyze and adopt trial and error procedure.The not vertical deformation of taking into account system earlier, and the quality of omitting vibration isolator, then mass of system does

M＝|2S ₁(D-H)+S ₂d|γ _c (13)

S in the formula ₁Be ground, room excavation area, this is 6m ²

D is a ground excavation height, and this is 0.2m;

S ₂Be about room area, this is 11.2m ²

D is a room floor thickness, and this is 0.05m;

H is the vibration isolator height;

γ _cProportion for earth material.

If the earth material design is made up of concrete, correspondingly, γ _cDesirable 2.4g/cm ³When H gets recommended value 3cm, try to achieve M by formula (13) and be about 6.24 * 10 ³Kg.

2) the quiet stiffness K of vibrating isolation system _Zs

According to formula (1), can get K _ZsEqual 1.1 * 10 ⁴(N/cm), wherein, W _I, N, ρ gets 300Kg, 28,0.1mm respectively.

3) system free vibration frequency f _nThe dynamic stiffness K of system _zFor

K _z＝n _dK _zs (14)

N in the formula _dFor the dynamic and static ratio of rigidity of elastomeric material, get 2.5, get K _zEqual 2.8 * 10 ⁴(N/cm).With K _zThe weight m=M/N=240kg that value and each vibration isolator bear (N is for laying the number of rubber shock absorber) substitution formula (2) gets f _nBe 17Hz.f _nObviously satisfy the requirement of formula (12).

4) system's vibration isolating effect.Get according to formula (7), formula (10) and formula (11)

${\mathrm{\&eta;}}_0<{\mathrm{\&eta;}}_a=\sqrt{\frac{1+4\&times;{0.1}^2\&times;\frac{{70.7107}^2}{{17}^2}}{{(1-\frac{{70.7107}^2}{{17}^2})}^2+4\&times;{0.1}^2\&times;\frac{{70.7107}^2}{{17}^2}}}=8\%$

T ₀＞|1-η _a|＝92％

L _a0＜99η ₀＝8(dB)

After promptly adopting vibration isolation scheme of the present invention, the peak acceleration level of centre frequency 80Hz1/3 octave, than " indoor vibration limit value of housing construction and measuring method standard thereof " in (GB/50355-2005) corresponding limit value reduce 87dB, vibration isolation efficiency reaches 92%.

The above-mentioned description to embodiment is can understand and use the present invention for ease of the those of ordinary skill of this technical field.The personnel of skilled obviously can easily make various modifications to these embodiment, and needn't pass through performing creative labour being applied in the General Principle of this explanation among other embodiment.Therefore, the invention is not restricted to the embodiment here, those skilled in the art should be within protection scope of the present invention for improvement and modification that the present invention makes according to announcement of the present invention.

Claims (7)

1. indoor vibration isolation method for existent buildings at subway operation section is characterized in that: each room of existing building bottom of iron Operational Zone carries out integral body excavation, tamped backfill more over the ground; Tamped backfill is divided into bottom, intermediate layer and top layer, and bottom is the vibration isolation core layer, is made up of rubber shock absorber; The intermediate layer is a C20 plain concrete layer, and top layer is general room ground, and fill with polymeric foam boards in the space between three decks;

This rubber shock absorber adopts high duty metal thin layer or the artificial synthetic extraordinary compounded rubber of lamination, and the quiet rigidity of rubber is by indoor dynamic load W _I, vibration isolator number N and Land-Subsidence Control displacement ρ confirm jointly, satisfy $\frac{W_I}{N}\frac{1}{K_{\mathrm{Zs}}}<\mathrm{\&rho;}\left(\mathrm{Mm}\right).$

2. indoor vibration isolation method for existent buildings at subway operation section as claimed in claim 1 is characterized in that: this vibration isolation core layer height >=35mm, it is made up of a plurality of discrete vibration isolators.

3. indoor vibration isolation method for existent buildings at subway operation section as claimed in claim 2 is characterized in that: the spacing between this vibration isolator is≤500mm.

4. indoor vibration isolation method for existent buildings at subway operation section as claimed in claim 2 is characterized in that: the height >=30mm of this vibration isolator, its bottom surface >=150mm * 150mm.

5. indoor vibration isolation method for existent buildings at subway operation section as claimed in claim 1 is characterized in that: the thickness >=100mm in this intermediate layer.

6. indoor vibration isolation method for existent buildings at subway operation section as claimed in claim 1 is characterized in that: this top layer carries out after 24 hours pouring the intermediate layer.

7. indoor vibration isolation method for existent buildings at subway operation section as claimed in claim 1 is characterized in that: each room has an independently vibration isolation system of one's own.

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