CN209538249U - A kind of building liquid buoyancy laboratory testing rig - Google Patents
A kind of building liquid buoyancy laboratory testing rig Download PDFInfo
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- CN209538249U CN209538249U CN201822069191.3U CN201822069191U CN209538249U CN 209538249 U CN209538249 U CN 209538249U CN 201822069191 U CN201822069191 U CN 201822069191U CN 209538249 U CN209538249 U CN 209538249U
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Abstract
The utility model relates to a kind of building liquid buoyancy laboratory testing rigs, including excavation models case (1), insert the medium soil layer (6) of the excavation models case (1), it is located at medium soil layer (6) middle and upper part, the building model case (2) that bottom plate and side wall are contacted with the soil body, is located at the pressure sensor (3) and pore pressure gauge (5) being placed in the soil body below building model case (2) bottom plate；The building model case (2) is in 45 degree between side wall and horizontal plane.In the utility model, it is in 45 degree between building model case side wall and horizontal plane, the side friction of the soil body and structure side wall can be effectively eliminated, the F for obtaining testFloating test valueCloser to true value；The use of pressure sensor and pore pressure gauge can accurately obtain F at that timeFloating test value.To sum up, the utility model effectively increases FFloating test valueAccuracy, and then ensure that the accuracy of reduction coefficient K, finally can be avoided the waste of lot of materials, reduce project cost.
Description
Technical field
The utility model relates to try in basic uplift pressure the field of test technology more particularly to a kind of building liquid buoyancy room
Experiment device.
Background technique
In recent years, with the development and utilization of urban underground space, underground structure, structures are (for sake of simplicity, herein to build
Object is built to be illustrated for representative) buoyancy problem gradually highlight, in building foundation pit digging process, often take
Corresponding dewatering measure, level of ground water can be gradually restored to ordinary water level over time after the completion of basis, this meeting pair
It is basic to generate larger buoyancy, if fabric structure self weight is not able to satisfy anti-floating requirement, and without using reasonable measure of anti float just
It will cause the generation of engineering accident, engineering accident common at present has: (1) underground structure is integrally floated；(2) underground structure
Heave；(3) underground structure local failure of structure, this certainly will need to carry out Anti-floating design research to underground structure.
When building floats in liquid water, suffered buoyancy can use Archimedes principle p=γwHA is calculated,
In, γwFor the severe of water, h is the head height of underground structure bottom plate or more, and A is underground structure floor space；When building is close
When in real waterproof dielectric layer, suffered buoyancy is zero, will not be floated；When building floats in permeable leakiness dielectric layer
When, suffered buoyancy can be determined between the above two by carrying out a degree of reduction to Archimedes principle buoyancy.Tool
The reduction coefficient K of body is obtained by liquid buoyancy laboratory test, reduction coefficient K=FFloating test value/FFloating theoretical value, FFloating theoretical valueFor simulant building
The building case of object suffered theory buoyancy size when floating completely in liquid water, is calculated by Archimedes principle,
FFloating test valueFor when building case in respective media suffered buoyancy size, obtained by laboratory test.
During existing liquid buoyancy laboratory test, building is simulated with rectangular iron water tank.However this
Kind analog form can not eliminate the frictional resistance between the soil body and structure side wall, and can not also learn in test the part frictional resistance
Power specific value size.According to the actual loading situation of building, the structure vertically eventually effect by three kinds of power: FSide+W
=FIt is floating, W is fabric structure self weight, FSideIt is the soil body to the side friction of texture edge, FIt is floatingIt is underground water to structure basis bottom plate
Buoyancy；Due to FSideUnknown, we can not accurately obtain W and FIt is floatingBetween relationship.Laboratory test is returned to, due to FSideIt is unknown, examination
The F testedFloating test valueIt is universal bigger than normal, so that keep reduction coefficient K bigger than normal, if the test data is applied to be bound in engineering practice
Lot of materials can be wasted, increases project cost (because to guarantee that building self weight W is greater than underground water to the buoyancy F of structureIt is floatingIf
FIt is floatingBigger than normal, W is naturally also just bigger than normal).
Utility model content
The technical problem to be solved by the utility model is to provide a kind of building liquid buoyancy laboratory testing rigs, with solution
The side friction generated because that cannot eliminate the soil body to structure side wall in certainly existing test causes reduction factor of buoyancy is bigger than normal to ask
Topic.
To solve the above problems, a kind of building liquid buoyancy laboratory testing rig described in the utility model, the device
Including excavation models case, the medium soil layer of the excavation models case is inserted, is located at medium soil layer middle and upper part, bottom plate and side wall
The building model case contacted with the soil body is located at the pressure sensor being placed in the soil body below the building model bottom plate
And pore pressure gauge；The pressure sensor is for detecting the building model case to the pressure value of lower section soil layer；It is described
It is in 45 degree between building model case side wall and horizontal plane.
Preferably, the building model case is integrally in positive quadrangular frustum pyramid shaped.
Preferably, the quantity of the pressure sensor is multiple, is evenly distributed on the building model bottom plate center
And surrounding.
Preferably, the medium soil layer includes clay, coarse sand, fine sand, Extra-fine sand, loess or Red Sandstone.
Preferably, which further includes the cement sand bed being located on the building model bottom plate and side wall.
Compared with the prior art, the utility model has the following advantages:
In the utility model, between (1) building model case side wall and horizontal plane be in 45 degree, can effectively eliminate the soil body and
The side friction of structure side wall makes buoyancy be numerically equal to dead load i.e. W=FIt is floating, make to test obtained FFloating test valueCloser to
True value；(2) use of pressure sensor and pore pressure gauge can accurately obtain F at that timeFloating test value.To sum up, this is practical
It is novel to effectively increase FFloating test valueAccuracy, and then ensure that the accuracy of reduction coefficient K, finally can be avoided lot of materials
Waste, reduce project cost.
Detailed description of the invention
Specific embodiment of the present utility model is described in further detail with reference to the accompanying drawing.
Fig. 1 is a kind of longitudinal section view of building liquid buoyancy laboratory testing rig provided by the embodiment of the utility model
Figure.
Fig. 2 is a kind of top view of building liquid buoyancy laboratory testing rig provided by the embodiment of the utility model.
Fig. 3 is the floor plan of pressure sensor provided by the embodiment of the utility model and pore pressure gauge.
In figure: 1-excavation models case, 2-building model casees, 3-pressure sensors, 4-liquid waters, 5-pore waters
Pressure gauge, 6-medium soil layers.
Specific embodiment
With reference to Fig. 1~2, the utility model embodiment provides a kind of building liquid buoyancy laboratory testing rig, the device
Excavation models case 1 is specifically included, the medium soil layer 6 of excavation models case 1 is inserted, is located at 6 middle and upper part of medium soil layer, bottom plate and side wall
The building model case 2 contacted with the soil body is located at the pressure sensor 3 being placed in the soil body below 2 bottom plate of building model case
With pore pressure gauge 5.
It is in 45 degree between above-mentioned 2 side wall of building model case and horizontal plane.In practical applications, building model case 2 has
Body can be in positive quadrangular frustum pyramid shaped using entirety without top iron and screw case；Excavation models case 1 is in cuboid without top iron and screw case.
Pressure sensor 3 is used to detect the pressure value of 2 pairs of lower section soil layers of building model case.Further, pressure sensing
The quantity of device 3 be it is multiple, be evenly distributed on 2 bottom plate center of building model case and surrounding.For example, for building model case 2
The case where in positive quadrangular frustum pyramid shaped, bottom plate are a square plate, and pressure sensor 3 and pore pressure gauge 5 are below bottom plate
Deployment scenarios can refer to Fig. 3, in figure, be respectively provided with one on four angles in bottom plate center and surrounding, pressure sensor 3, pore water
Pressure gauge 5 is located at bottom plate immediate vicinity.
For in the manufacturing process of experimental rig, for example: building model case 2 is in positive quadrangular frustum pyramid shaped；By foundation pit mould
The height of molding box 1 is divided into 15 equal portions, and the height of building model case 2 is that six equal portions are thick；(1) it is first filled out toward excavation models case 1
Enter the medium soil layer 6 of five equal portions thickness, (2) arrange pressure sensor 3 in 6 center of medium soil layer, by above-mentioned position mode
With pore pressure gauge 5, building model case 2 is placed on medium soil layer 6 by (3), is in close contact bottom and the soil body, is paid attention to wanting
Ensure that bottom center is aligned with the pressure sensor 3 for being in center, (4) are last to insert six equal portions thickness toward excavation models case 1 again
Medium soil layer 6,6 top surface of medium soil layer is concordant with 2 top of building model case at this time, completes the production of experimental rig.
In view of suffered buoyancy is of different sizes when building model case 2 floats in different medium layer, therefore, medium soil layer
6 can be one of media such as clay, coarse sand, fine sand, Extra-fine sand, loess and Red Sandstone, and it is real to be specifically chosen any view
Depending on the demand of border.Wherein, Red Sandstone be the Northwest is distinctive have in weak water penetration red sand ground.Certainly, in reality
In the application of border, simulation laboratory test can all be done to these media, obtain the building sole plate institute in different medium soil layer
Bear water buoyancy size, and then calculate corresponding reduction coefficient, so as to study water buoyancy suffered by building sole plate with not
With the relationship between medium soil layer soil body physical property.
Further, utility model device can also include the cement being located on 2 bottom plate of building model case and side wall
Screed；Connection is realized by cement mortar binder between cement mortar and building model case 2.This mode can make to build
It builds water buoyancy suffered by 2 bottom plate of object model casing and side wall and building model case 2 is transmitted to by cement mortar, to change medium soil
Soil cracking behavior is eliminated in the particle way of contact between 6 soil body of layer and building model case 2.By comparing analysis such case
Buoyancy size suffered by lower 2 bottom plate of building model case and under normal circumstances buoyancy size, can study soil cracking behavior to building
The influence that water buoyancy size suffered by object sole plate generates.
Here the side friction that 45 degree can be effectively eliminated with the soil body and structure side wall, makes the variable quantity of buoyancy numerically
Equal to the variation delta W=Δ F of dead loadIt is floatingIt is explained: according to Coulomb's earth pressure formula
In formula: the severe that γ-bankets, KN/m3；
- the internal friction angle banketed, degree；
α-wall back inclination angle, degree take positive sign, negative sign are taken when facing upward oblique when bowing oblique；
β-rolling earth behind retaining wall face inclination angle, degree.
In above formula, γ, h, α, β andφ be all it is known, what the angle theta of sliding surface and horizontal plane assumed that.If false
Determine angle theta=45 ° between sliding surface and horizontal plane, 2 side wall of building model case is allowed to replace the soil body in the present invention
Sliding surface, then side wall and the angle of horizontal direction are 45 degree, then according to the shape wall back of building model case 2 to face upward tiltedly, institute
With available α=- 45 °, then in substitution formula, due to cos (θ-α)=0, so E=0, builds to would not also generate and work as
Build the side friction that the soil body gives texture edge when object floats.It is effective by the bottom edge angle for changing simulant building thing model casing
The side friction for eliminating soil body particle and structure side wall generation, makes buoyancy be numerically equal to dead load i.e. W=FIt is floating。
Disclosed building liquid buoyancy laboratory testing rig based on the above embodiment, another embodiment of the utility model is also
A kind of building liquid buoyancy Experimental Method in Laboratory is accordingly provided, this method specifically comprises the following steps:
(1) water is added into medium soil layer 6 in excavation models case 1, until water logging is less than 6 top surface of medium soil layer.
(2) add water into building model case 2, fit closely building model case 2 and the soil body and be not in float state,
It is then allowed to stand a period of time, medium soil layer 6 is allowed to reach saturation state.
(3) after the completion of standing, the water in building model case 2 is gradually taken away, and is found referring to 3 registration of pressure sensor
The moment that building model case 2 floats.
(4) stop draining immediately when floating moment wait search out, and according to the registration and building of pore pressure gauge 5 at this time
The buoyancy size suffered by 6 insole board of medium soil layer of building model case 2 is calculated in 2 base areas of object model casing.
When the registration for having pressure sensor 3 is 0, it is believed that the moment floated at this time for building model case 2, building mould
The self weight of molding box 2 is equal to underground water to the water buoyancy of 2 bottom plate of building model case.What needs to be explained here is that ideally,
Should just float moment at last when the registration of all pressure sensors 3 is zero, but in practical operation, have
The registration of pressure sensor 3 is regarded as floating moment when being 0.
According to force analysis, have in reflection to building model case 2 and pore pressure gauge 5:
In formula: G is the self weight of building model case 2, FFloating test valueFor buoyancy suffered by 2 bottom plate of building model case, f is pressure biography
The registration of sensor 3；P is the registration of pore pressure gauge 5, and S is 2 base areas of building model case.As it can be seen that pressure sensor 3
Registration is to float moment for finding building model case 2,5 registration of pore pressure gauge be for building model case 2
F is calculated in base areas S multiplicationFloating test value.Obtaining FFloating test valueAfterwards, according to formula K=FFloating test value/FFloating theoretical valueCalculate reduction coefficient
K；It is understood that F hereFloating theoretical valueIt is calculated according to Archimedes principle.
Further, this method further include: cement sand bed is set on 2 bottom plate of building model case and side wall, is calculated
In this case buoyancy size suffered by 2 bottom plate of building model case out, and pass through to the buoyancy size and under normal circumstances buoyancy
Size is compared analysis, the influence that research soil cracking behavior generates water buoyancy size suffered by building sole plate.
Technical solution provided by the utility model is described in detail above.Specific case pair used herein
The principles of the present invention and embodiment are expounded, and the above embodiments are only used to help understand, and this is practical new
The method and its core concept of type.It is practical not departing from it should be pointed out that for those skilled in the art
Under the premise of new principle, several improvements and modifications can be made to this utility model, these improvement and modification also fall into this
In the protection scope of utility model claims.
Claims (5)
1. a kind of building liquid buoyancy laboratory testing rig, which is characterized in that the device includes excavation models case (1), filling
The medium soil layer (6) of the excavation models case (1) is located at medium soil layer (6) middle and upper part, bottom plate and side wall and connects with the soil body
The building model case (2) of touching is located at the pressure sensor (3) being placed in the soil body below building model case (2) bottom plate
With pore pressure gauge (5)；The pressure sensor (3) is for detecting the building model case (2) to the pressure of lower section soil layer
Force value；The building model case (2) is in 45 degree between side wall and horizontal plane.
2. device as described in claim 1, which is characterized in that the building model case (2) is integrally in positive quadrangular frustum pyramid shaped.
3. device as described in claim 1, which is characterized in that the quantity of the pressure sensor (3) be it is multiple, be uniformly distributed
In building model case (2) the bottom plate center and surrounding.
4. device as described in claim 1, which is characterized in that the medium soil layer (6) includes that clay, coarse sand, fine sand, powder are thin
Sand, loess or Red Sandstone.
5. the device as described in Claims 1-4 any one, which is characterized in that the device further includes being located at the building
Cement sand bed on model casing (2) bottom plate and side wall.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201822069191.3U CN209538249U (en) | 2018-12-11 | 2018-12-11 | A kind of building liquid buoyancy laboratory testing rig |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201822069191.3U CN209538249U (en) | 2018-12-11 | 2018-12-11 | A kind of building liquid buoyancy laboratory testing rig |
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| Publication Number | Publication Date |
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| CN209538249U true CN209538249U (en) | 2019-10-25 |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109555168A (en) * | 2018-12-11 | 2019-04-02 | 兰州理工大学 | A kind of building liquid buoyancy laboratory testing rig and test method |
| CN115359713A (en) * | 2022-06-02 | 2022-11-18 | 安徽省建筑科学研究设计院 | Underground water buoyancy model system |
-
2018
- 2018-12-11 CN CN201822069191.3U patent/CN209538249U/en active Active
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109555168A (en) * | 2018-12-11 | 2019-04-02 | 兰州理工大学 | A kind of building liquid buoyancy laboratory testing rig and test method |
| CN109555168B (en) * | 2018-12-11 | 2024-04-09 | 兰州理工大学 | Building liquid buoyancy indoor test device and test method |
| CN115359713A (en) * | 2022-06-02 | 2022-11-18 | 安徽省建筑科学研究设计院 | Underground water buoyancy model system |
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Addressee: Yang Kuibin Document name: Special letter for review business |
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