CN106120838A - A kind of basic constructional design method of the gravity type spread foundation of vertical shaft fan - Google Patents

Abstract

The invention discloses the basic constructional design method of the gravity type spread foundation of a kind of vertical shaft fan, belong to wind electric field blower foundation construction field, including step: A: fan loads value is adapted to the standard value of fan loads；B: in normal conditions, determines foundation bottom radius；C: under extreme operating condition, determines foundation bottom radius；D: select the foundation bottom radius that can simultaneously meet nominal situation and extreme operating condition；E: according to formula h₂≥0.38×(r₂‑r₁), determine basis root thickness；The gravity type spread foundation that the present invention designs is applied to vertical shaft fan on the premise of satisfied safety, it is capable of the carrying out to gravity type spread foundation is more economical to build, under the conditions of design parameter, Con trolling index are all rational, the present invention is mainly by optimizing original payload data and with reference to base structure is optimized design, to reach to reduce blower foundation concrete and steel project, save construction investment.

Description

A kind of basic constructional design method of the gravity type spread foundation of vertical shaft fan

Technical field

The present invention relates to wind electric field blower foundation construction field, the gravity type spread foundation of a kind of vertical shaft fan Basic constructional design method.

Background technology

First of the domestic or even world high-power vertical shaft blower fan of wind-powered electricity generation research inspection center of country development & production, mainly special Point is as follows: blower fan work wind speed range is big, and its work wind speed range is: 2.8m/s～35m/s；Except under artificial or emergency conditions Outside shutdown, normal power generation all the time in work wind speed range；Electromotor is around vertical axis, higher to ground deformation requirements.

The specification that the Wind turbines basic constructional design carried out at present calculates, is both for the blower foundation of trilobal formula Carry out specifying, be typically based on the load data of the Wind turbines that blower fan producer provides, combine neighbouring Sinilar engineering geological conditions, Selecting base form, the design then carrying out base structure calculates；And to the design of vertical shaft fan base structure currently without The standard determined, on the basis of typically the computational methods of the blower foundation of trilobal formula being applied to vertical shaft fan, but, by Normal power generation under vertical shaft fan is at high wind speed, during normal power generation, operating mode load is big, and the method for operation of vertical shaft fan is to wind The impact of machine basic engineering: cause foundation bottom area to need to increase, increase foundation concrete amount, thus add the engineering of capital construction Amount, affects project progress.

Summary of the invention

The technical issues that need to address of the present invention are to provide the basis knot of the gravity type spread foundation of a kind of vertical shaft fan Structure method for designing, actual condition reduces foundation concrete amount while needing to make gravity type spread foundation disclosure satisfy that, saves basis and builds If expense.

For solving above-mentioned technical problem, the technical solution adopted in the present invention is:

The basic constructional design method of the gravity type spread foundation of a kind of vertical shaft fan, it is characterised in that include following Step:

Step A: by fan loads value with load correction safety coefficient K₀=1.35 are modified, obtain at nominal situation and The standard value of fan loads under extreme operating condition.

Step B: in normal conditions, calculates base stress with the standard value that step A obtains, so that it is determined that foundation bottom half Footpath；

Step C: under extreme operating condition, calculates base stress with the standard value that step A obtains, so that it is determined that foundation bottom half Footpath；

Step D: foundation bottom radius distance value step B, C obtained compares, selects and can meet normal work simultaneously The foundation bottom radius of condition and extreme operating condition；

Step E: according to formula h₂≥0.38×(r₂-r₁), determine basis root thickness, wherein h₂Based on root thickness, r₂Based on bottom radius, r₁Based on top radius.

Further improvement is that of technical solution of the present invention: calculate the formula of base stress in described step B and step C For:

${\mathrm{\σ}}_{min}^{max}=\frac{N+G}{A}\±\frac{M_X+M_Y+M{1}_X+M{1}_Y}{W};$

Wherein, A is the area of substrate, A=π r₂ ²；

W is area resistance moment,

N is the load force standard value of Z-direction；

Based on G and the gravity of earthing；

M_XThe moment of flexure produced for the load force standard value of X-direction；

M_YThe moment of flexure produced for the load force standard value of Y-direction；

M1_XFor X-direction load force standard value produce additional bending moment, the concrete load force standard value for X-direction with The product of height of foundation H；

M1_YFor Y-direction load force standard value produce additional bending moment, the concrete load force standard value for Y-direction with The product of height of foundation H.

Further improvement is that of technical solution of the present invention: according to base stress maximum less than ground in described step B Bearing capacity, and the requirement that base stress minima is more than zero, carry out the determination of foundation bottom diameter.

Further improvement is that of technical solution of the present invention: according to base stress maximum less than ground in described step C Bearing capacity, and the area of substrate disengagement ground is less than the requirement of the substrate gross area 25%, carries out the determination of foundation bottom diameter.

Further improvement is that of technical solution of the present invention: the computing formula of the area that substrate disengages ground is:

$A_1={r_2}^2\×{\cos }^{-1}(\mathrm{\τ}-1)-\frac{1}{2}{r_2}^{2}sin\[2{\cos }^{-1}(\mathrm{\τ}-1)\];$

Wherein the value of τ is according to eccentricity with joint effortsThe value obtained determines.

Owing to have employed technique scheme, the technological progress that the present invention obtains is:

The gravity type spread foundation that the present invention designs is applied to vertical shaft fan on the premise of satisfied safety, it is possible to real Now the carrying out that gravity type spread foundation is more economical is built, under the conditions of design parameter, Con trolling index are all rational, master of the present invention Will be by optimizing original payload data and with reference to base structure is optimized design, to reach to reduce blower foundation concrete And steel project, save construction investment.

The basic root thickness that the present invention is directed to gravity type spread foundation uses empirical equation to calculate, the basic root drawn Thickness can effective control critical eigenvalue width, reduce foundation concrete amount the most to greatest extent, save engineering cost；For gravity type The foundation bottom radius of spread foundation uses the formula of base stress to calculate, meet substrate the most do not disengage ground, Under extreme operating condition, disengage the area of base requirement less than the substrate gross area 25%, and then obtain the minimum of foundation bottom radius Value, reduces foundation concrete amount to greatest extent while meeting base stress requirement, save engineering cost.

Accompanying drawing explanation

Fig. 1 is the schematic front view of gravity type spread foundation in the present invention；

Fig. 2 is the schematic top plan view of gravity type spread foundation in the present invention；

Fig. 3 is the schematic perspective view of gravity type spread foundation in the present invention；

Wherein, r₁Based on top radius, r₂Based on bottom radius, based on H height, buried depth based on d, h₂For base Plinth root thickness, h₁Based on end thickness.

Detailed description of the invention

A kind of gravity type spread foundation of vertical shaft fan as shown in Figure 1, Figure 2, Figure 3 shows, described gravity type spread foundation Basic constructional design method, comprise the following steps:

Step A: obtain vertical shaft fan lotus respectively under nominal situation and extreme operating condition according to the data that producer provides Carry table, and according to load correction safety coefficient K₀=1.35 revise characteristic value of load, determine that vertical shaft fan is respectively in normal work Load force standard value F that X under condition and extreme operating condition, Y, Z-direction produce_X、F_YAnd F_Z, and the moment of flexure that above load force produces Standard value M_X、M_YAnd M_Z。

Then the bearing capacity of foundation soil is determined according to geologic information.

Step B: in normal conditions, it is assumed that a foundation bottom radius value, and use below equation to calculate base stress.

${\mathrm{\σ}}_{min}^{max}=\frac{N+G}{A}\±\frac{M_X+M_Y+M{1}_X+M{1}_Y}{W};$

Wherein, A is the area of substrate, A=π r₂ ²；

W is area resistance moment,

N is the load force standard value of Z-direction；

Based on G and the gravity of earthing；

M_XThe moment of flexure produced for the load force standard value of X-direction；

M_YThe moment of flexure produced for the load force standard value of Y-direction；

M1_XFor X-direction load force standard value produce additional bending moment, the concrete load force standard value for X-direction with The product of height of foundation H；

M1_YFor Y-direction load force standard value produce additional bending moment, the concrete load force standard value for Y-direction with The product of height of foundation H.

Calculate base stress according to above-mentioned formula, make base stress meet maximum less than bearing capacity of foundation slab, and The requirement more than zero of the little value, thus obtain the minima of foundation bottom radius.

Step C: under extreme operating condition, it is assumed that a foundation bottom radius value, and use below equation calculating base stress:

${\mathrm{\σ}}_{min}^{max}=\frac{N+G}{A}\±\frac{M_X+M_Y+M{1}_X+M{1}_Y}{W};$

Calculate base stress according to above-mentioned formula, make base stress meet maximum less than bearing capacity of foundation slab, now base The minima negative value of bottom stress, substrate disengageably primary surface, the area that should calculate substrate disengagement ground makes disengagement area less than base The 25% of the end gross area, thus obtain the minima of foundation bottom radius.

The computing formula of the area that substrate disengages ground is:

$A_1={r_2}^2\×{\cos }^{-1}(\mathrm{\τ}-1)-\frac{1}{2}{r_2}^{2}sin\[2{\cos }^{-1}(\mathrm{\τ}-1)\];$

Wherein the value of τ is according to eccentricity with joint effortsThe value obtained determines, with specific reference to work For make a concerted effort eccentric throw and the ratio of base radius of substrate, i.e.Value, by 3 values drawing τ of tabling look-up.

Step D: foundation bottom radius distance value step B, C obtained compares, and be substituted for each other and calculate, select The foundation bottom radius of nominal situation and extreme operating condition can be met simultaneously.

Step F: according to formula h₂≥0.38×(r₂-r₁), determine the minima of basis root thickness, r₂Bottom based on Radius, r₁Based on top radius, r₁Concrete numerical value according to blower fan require determine, basis root thickness h₂Determination mode energy Enough meet the linear requirements of base structure, and utilize basic root thickness h that above-mentioned formula obtains₂Can effective control critical eigenvalue Width, meets the requirement of fracture width ＜ 0.2mm.

The determination of embedded depth of foundation d should meet the standard of the requirement of foundation bearing capacity, deformation and stability, the simultaneously greater than soil body Freeze deep.

The determination of height of foundation H should meet basis and elevate above the soil the requirement of 300mm, i.e. H=d+300mm.

Base end thickness h₁According to the standard of " FD003-2007 Wind turbines Base foundation design specifies ", take minima 1m；Base end thickness h in the present invention₁With basis root thickness h₂All take minima, want meeting underlying strength and fracture width On the premise of asking, the most less foundation concrete amount, save construction investment.

Below in conjunction with embodiment, the present invention is described in further details.

Embodiment 1:

Vertical shaft fan load respectively under nominal situation and extreme operating condition is determined, such as table according to the data that producer provides 1。

Table 1:

Vertical shaft fan payload values producer provided is with load correction safety coefficient K₀=1.35 are modified, and obtain table 2。

Table 2:

The bearing capacity of foundation soil is determined according to geologic information:

Foundation bearing capacity f_a=800kPa.

According to step B: in normal conditions, calculate base stress with the standard value of table 2, so that it is determined that foundation bottom half Footpath.

Calculating is assumed foundation bottom radius r₂=9m；Below equation is used to carry out the calculating of base stress.

${\mathrm{\σ}}_{min}^{max}=\frac{N+G}{A}\±\frac{M_X+M_Y+M{1}_X+M{1}_Y}{W};$

Wherein, the area A=π r of substrate₂ ²=254.34.

W is area resistance moment,

N be the load force standard value of Z-direction be 4240.755kN.

Based on G and the gravity of earthing is 17803.8kN.

M_XThe moment of flexure produced for the load force standard value of X-direction is 0kN.

M_YThe moment of flexure produced for the load force standard value of Y-direction is 40358.25kN.

M1_XFor X-direction load force standard value produce additional bending moment, the concrete load force standard value for X-direction with The product of height of foundation H；

Height of foundation H freezes deeply according to ground and embedded depth of foundation is defined as 3.8m, draws M1_XFor 2094.6kN*m.

M1_YThe additional bending moment produced for the load force standard value of Y-direction is 0kN*m.

Finally drawing, base stress maximum is 160.8kN/, and base stress minima is 12.6kN/, meets and wants Ask.

According to step C: under extreme operating condition, calculate base stress with the standard value of table 2, so that it is determined that foundation bottom half Footpath.

Assume foundation bottom radius r₂=10m；Below equation is used to carry out the calculating of base stress.

${\mathrm{\σ}}_{min}^{max}=\frac{N+G}{A}\±\frac{M_X+M_Y+M{1}_X+M{1}_Y}{W};$

Wherein, the area A=π r of substrate₂ ²=314.0.

W is area resistance moment,

N be the load force standard value of Z-direction be 4169.475kN.

Based on G and the gravity of earthing is 21980KN.

M_XThe moment of flexure produced for the load force standard value of X-direction is 0kN.

M_YThe moment of flexure produced for the load force standard value of Y-direction is 104352.3kN.

M1_XFor X-direction load force standard value produce additional bending moment, the concrete load force standard value for X-direction with The product of height of foundation H；

Height of foundation H freezes deeply according to ground and embedded depth of foundation is defined as 3.8m, draws M1_XFor 7432.614kN*m.

M1_YThe additional bending moment produced for the load force standard value of Y-direction is 0kN*m.

Finally drawing, base stress maximum is 225.571kN/, and base stress minima is-59kN/, and substrate should Power maximum meets requirement.

Further, calculate substrate maximum and disengage area.

First the eccentric throw of making a concerted effort of substrate is acted onObtain

Then basisValue, look into such as table 3 below, the value obtaining τ is 1.432.

Table 3

e/r2	τ	e/r2	τ	e/r2	τ	e/r2	τ
								0.25	2.000	0.352	1.6540	0.373	1.5910	0.41	1.482
0.26	1.960	0.353	1.6510	0.377	1.5790	0.413	1.4740
								0.27	1.932	0.356	1.6420	0.378	1.5760	0.415	1.4685
0.28	1.890	0.357	1.6390	0.38	1.570	0.416	1.4658
								0.29	1.858	0.358	1.6360	0.382	1.5644	0.418	1.4604
0.30	1.820	0.36	1.630	0.384	1.5588	0.42	1.455
								0.31	1.787	0.361	1.6270	0.39	1.542	0.421	1.447
0.32	1.755	0.363	1.6210	0.393	1.5330	0.422	1.4388
								0.33	1.723	0.364	1.6180	0.40	1.512	0.427	1.433
0.34	1.692	0.367	1.6090	0.404	1.5000	0.428	1.431
								0.35	1.660	0.37	1.600	0.407	1.4910	0.43	1.428

Calculate basis bearing width a=τ * r₂=14.32.

Calculate and disengage area

Basis disengages area and accounts for the ratio of the gross area

Finally drawing, substrate maximum disengages area and meets the requirement less than the substrate gross area 25%.

But now obtain two base radius, respectively 9m and 10m according to nominal situation one and extreme operating condition two.

According to step D: two base radius 9m and 10m are compared, obtain meeting step C, D requires simultaneously The a diameter of 10m in basis；Show that base radius is played a decisive role by extreme operating condition two simultaneously.

According to step E: determine basis root thickness.

With specific reference to formula h₂≥0.38×(r₂-r₁), calculate the minima that basis root needs.

Wherein r₁Based on top radius, according to the parameter determination of vertical shaft fan, r in the present embodiment₁Take 3.2m.

Thus draw h₂Minimum 2.58m, takes approximation 2.6m.

Embedded depth of foundation d is defined as 3.5m.

Height of foundation H meets basis and elevates above the soil the requirement of 300mm, is defined as 3.8m.

Base end thickness h₁According to the standard of " FD003-2007 Wind turbines Base foundation design specifies ", take minima 1m。

Claims (5)

1. the basic constructional design method of the gravity type spread foundation of a vertical shaft fan, it is characterised in that include following step Rapid:

Step A: by fan loads value with load correction safety coefficient K₀=1.35 are modified, and obtain at nominal situation with extreme The standard value of fan loads under operating mode；

Step B: in normal conditions, calculates base stress with the standard value that step A obtains, so that it is determined that foundation bottom radius；

Step C: under extreme operating condition, calculates base stress with the standard value that step A obtains, so that it is determined that foundation bottom radius；

Step D: foundation bottom radius distance value step B, C obtained compares, select can meet simultaneously nominal situation and The foundation bottom radius of extreme operating condition；

Step E: according to formula h₂≥0.38×(r₂-r₁), determine basis root thickness, wherein h₂Based on root thickness, r₂For Foundation bottom radius, r₁Based on top radius.

The basic constructional design method of the gravity type spread foundation of a kind of vertical shaft fan the most according to claim 1, its It is characterised by: the formula calculating base stress in described step B and step C is:

${\mathrm{\σ}}_{min}^{max}=\frac{N+G}{A}\±\frac{M_X+M_Y+M{1}_X+M{1}_Y}{W};$

Wherein, A is the area of substrate, A=π r₂ ²；

W is area resistance moment,

N is the load force standard value of Z-direction；

Based on G and the gravity of earthing；

M_XThe moment of flexure produced for the load force standard value of X-direction；

M_YThe moment of flexure produced for the load force standard value of Y-direction；

M1_XThe additional bending moment produced for the load force standard value of X-direction, the concrete load force standard value for X-direction is high with basis The product of degree H；

M1_YThe additional bending moment produced for the load force standard value of Y-direction, the concrete load force standard value for Y-direction is high with basis The product of degree H.

The basic constructional design method of the gravity type spread foundation of a kind of vertical shaft fan the most according to claim 1 and 2, It is characterized in that: according to base stress maximum less than foundation bearing capacity in described step B, and base stress minima is more than The requirement of zero, carries out the determination of foundation bottom diameter.

The basic constructional design method of the gravity type spread foundation of a kind of vertical shaft fan the most according to claim 1 and 2, It is characterized in that: according to base stress maximum less than foundation bearing capacity in described step C, and substrate disengages the area of ground Less than the requirement of the substrate gross area 25%, carry out the determination of foundation bottom diameter.

The basic constructional design method of the gravity type spread foundation of a kind of vertical shaft fan the most according to claim 4, its It is characterised by: the computing formula of the area that substrate disengages ground is:

$A_1={r_2}^2\×{\cos }^{-1}(\mathrm{\τ}-1)-\frac{1}{2}{r_2}^{2}sin\[2{\cos }^{-1}(\mathrm{\τ}-1)\];$

Wherein the value of τ is according to eccentricity with joint effortsThe value obtained determines.