CN215562493U - Large-area flat plate load test platform for soft land area - Google Patents
Large-area flat plate load test platform for soft land area Download PDFInfo
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- CN215562493U CN215562493U CN202121673218.5U CN202121673218U CN215562493U CN 215562493 U CN215562493 U CN 215562493U CN 202121673218 U CN202121673218 U CN 202121673218U CN 215562493 U CN215562493 U CN 215562493U
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Abstract
The utility model provides a large-area flat plate load test platform in a soft soil area. The test platform comprises a reinforced concrete load-carrying plate, a stacking platform and a plurality of loading jacks; the stacking platform comprises a steel support, steel girders and a steel structure platform, the steel support is erected outside the load-carrying plate, the bottom of the steel support is provided with a reinforced concrete base, the steel structure platform is erected on the top of the steel support, the contact surfaces of the steel supports and the steel girders are provided with reinforced concrete pad beams, the steel girders are welded at the positions, corresponding to the load-carrying plate, of the bottom surface of the steel structure platform, and the steel girders are distributed at the positions, which are bisected or bilaterally symmetrical in the load-carrying plate; the plurality of loading jacks are uniformly distributed around the central point of the load bearing plate, the bottom of each loading jack is arranged on the load bearing plate, and the top of each loading jack is connected with the steel main beam in a propping manner. The utility model can carry out large-area platform stacking test, meets the requirements of design and construction, provides reliable supporting function for settlement deformation and calculation of earth volume, and has wide engineering application prospect.
Description
Technical Field
The utility model relates to a survey design construction technology for large-area site treatment engineering in a weak land area, in particular to a large-area flat plate load test platform for a large-area surcharge ultra-large flat plate load test in the weak land area, belonging to the field of foundation treatment in geotechnical engineering discipline.
Background
The flat plate load test is an in-situ test method which is earliest in use and most widely applied, the test is an in-situ test which applies load on a rigid bearing plate with a certain size in a grading way and observes the natural foundation soil along with pressure and deformation under the action of loads of all levels, and the flat plate load test can be used for: determining the bearing capacity of the foundation force according to the load-settlement relation line (curve); designing the deformation modulus of the soil; estimating the non-drainage shear strength and the limit filling height of the soil. At present, a load carrying plate in a flat plate load test generally adopts a steel plate, the size of the load carrying plate is usually not more than 3m, if the size is overlarge, the load carrying plate subjected to the load test is easy to deform, and a large-scale stacking platform is arranged on a soft soil foundation, so that the technical difficulty is high, and the support piers at two sides for supporting the stacking platform are easy to settle or destabilize; and the small-size loading plate has small stacking influence depth and cannot accurately reflect the property of the foundation soil.
Disclosure of Invention
The utility model provides a large-area flat plate load test platform for a weak soil area aiming at the problem that the existing flat plate load test load bearing plate is small in size and cannot accurately reflect the property of foundation soil.
In order to achieve the technical purpose, the utility model provides a large-area flat plate load test platform in a soft soil area, which comprises a load carrying plate, a stacking platform and a plurality of loading jacks, wherein the load carrying plate is an integrally cast-in-place reinforced concrete plate; the stacking platform comprises a steel support, steel girders and a steel structure platform, wherein the steel support is erected outside the load bearing plate, the bottom of the steel support is provided with a reinforced concrete base, the planar area of the steel structure platform is larger than that of the load bearing plate, the steel support is erected at the top of the steel support, the contact surfaces of the steel supports and the steel girders are provided with reinforced concrete pad beams, the steel girders are welded at the bottom surface of the steel structure platform corresponding to the load bearing plate, and the steel girders are distributed at the positions of the load bearing plate which are bisected or bilaterally symmetrical; the plurality of loading jacks are uniformly distributed around the central point of the load bearing plate, the bottom of each loading jack is arranged on the load bearing plate, and the top of each loading jack is connected with the steel main beam in a propping manner.
The utility model has the following excellent technical scheme: the load bearing plate is a reinforced concrete slab with the thickness of 0.5 m-0.6 m and is provided with double layers of reinforced net sheets, the diameter of a main rib phi 18 is longitudinally and transversely arranged, and the load bearing plate is provided with shear steel bars, and the strength grade of the concrete is C35.
The utility model has the following excellent technical scheme: the four loading jacks are symmetrically distributed in a load carrying plate according to a central line.
The utility model has the following excellent technical scheme: the steel structure platform is a steel beam platform formed by directly adopting steel secondary beams in a crossed mode, or a platform structure consisting of a steel beam structure formed by the steel secondary beams in a crossed mode and steel plates paved on the steel beam structure.
The utility model has the following excellent technical scheme: the steel support is composed of four steel structure buttresses with the width larger than 1m, the thickness of the clay covered on the reinforced concrete base at the bottom of the steel support is not smaller than 0.5m, a steel plate is embedded in the top surface of the reinforced concrete base, and the steel support is welded on the embedded steel plate.
The utility model has the following excellent technical scheme: the weight of the stacking platform adopts precast concrete test blocks, and the maximum loading capacity is determined to be 12000 kN.
The utility model has the following excellent technical scheme: and a steel base plate is embedded in the position of the load-carrying plate for mounting the loading jack.
The load carrying plate with the steel structure is replaced by the load carrying plate with the concrete structure, the area of the load carrying plate can be greatly increased by improving other structures, the area of the load carrying plate can reach 6m by 6m, the process of simulating large-area field stacking in an ultra-large flat plate load test can be realized, an accurate load-settlement P-S curve is obtained, settlement deformation of large-area stacking field treatment is calculated, and a settlement correction coefficient is determined by utilizing the principle that a settlement deformation theoretical calculation value is equal to an actual measurement value; the requirements of design and construction are met, a reliable supporting effect is provided for settlement deformation and calculation of earth volume, and the engineering application prospect is wide.
Drawings
FIG. 1 is a schematic structural view of the present invention;
FIG. 2 is a reinforcement diagram of the load plate of the present invention;
fig. 3 is a schematic view of the present invention in a stacked state.
In the figure: the method comprises the following steps of 1-a load bearing plate, 2-a loading jack, 3-a steel support, 4-a steel girder, 5-a steel structure platform, 6-a reinforced concrete pad beam, 7-a steel pad plate, 8-a reinforced concrete base and 9-a precast concrete test block.
Detailed Description
The utility model is further illustrated by the following figures and examples. Fig. 1 to 3 are drawings of embodiments, which are drawn in a simplified manner and are only used for the purpose of clearly and concisely illustrating the embodiments of the present invention. The following claims presented in the drawings are specific to embodiments of the utility model and are not intended to limit the scope of the claimed invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
In the description of the present invention, it is to be understood that the terms "upper", "lower", "inner", "outer", "left", "right", and the like, indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, or the orientations or positional relationships that the products of the present invention are conventionally placed in use, or the orientations or positional relationships that are conventionally understood by those skilled in the art, and are used for convenience of describing the present invention and simplifying the description, but do not indicate or imply that the equipment or elements referred to must have a specific orientation, be constructed in a specific orientation, and be operated, and thus, should not be construed as limiting the present invention.
The embodiment provides a large-area flat plate load test platform in a soft soil area, as shown in fig. 1 and fig. 2, the test platform comprises a load bearing plate 1, a stacking platform and a loading jack 2, the load bearing plate 1 is a 6m by 6m reinforced concrete plate, the thickness of the reinforced concrete plate is 0.5 m-0.6 m, a double-layer reinforced net piece is arranged in the load bearing plate 1, the diameter of a main rib is phi 18, the reinforced concrete plate is longitudinally and transversely arranged and provided with shear steel bars, and the strength grade of the concrete is C35. The stacking platform comprises a steel support 3, a steel girder 4 and a steel structure platform 5, wherein the steel support 3 consists of four steel structure buttresses with the width larger than 1m, the four steel structure buttresses are distributed on the outer side of the load bearing plate 1 and are respectively 2m away from the load bearing plate 1, a reinforced concrete base 8 at the bottom of the steel support 3 covers clay with the thickness not smaller than 0.5m, a steel plate is embedded in the top surface of the reinforced concrete base 8, and the steel support 3 is welded on the embedded steel plate; the plane area of the steel structure platform 5 is larger than the area of the load bearing plate 1, the steel structure is a platform structure consisting of a steel beam structure formed by crossing secondary steel beams and steel plates paved on the steel beam structure, the platform structure is erected at the top of the steel bracket 3, reinforced concrete pad beams 6 are arranged on the contact surfaces of the steel structure platform and the steel bracket 3, the steel main beams 4 are welded at the position, corresponding to the load bearing plate 1, of the bottom surface of the steel structure platform 5, and the steel main beams 4 are distributed at the positions of the split line or the bilateral symmetry of the split line of the load bearing plate 1; the four loading jacks 2 are uniformly distributed around the central point of the load bearing plate 1, the bottoms of the four loading jacks 2 are arranged on the load bearing plate 1, the tops of the four loading jacks 2 are connected with the steel main beam 4 in a propping manner, and a steel base plate 7 is embedded in the position of the load bearing plate 1 where the loading jacks 2 are installed.
The weight of the stacking platform adopts a precast concrete test block 9, and the maximum loading capacity is determined to be 12000 kN.
The utility model adopts fractional loading when the platform is loaded, and the load weight on the platform is always kept 1.5 times of the loading capacity, so that the buttress and the load bearing plate simultaneously share the load of the stacking platform. Because the soft soil layer has poor engineering property and large layer thickness, has large compression settlement (the settlement amount of 1m is preliminarily estimated before the test), and far exceeds the range (maximum 15cm) of the jack, the load is directly applied to the buttress to cause large deformation or damage of the buttress in order to ensure that the test process is continuously carried out and the jack can not be used for reducing the load. Therefore, the test loading system consists of 4 500T jacks, when the range of the jacks is reached each time, the load of one jack is unloaded, 15 cm-thick high-strength cushion blocks are plugged on the jacks, then the jacks are pressurized and restored to a stress state, cushion blocks are sequentially plugged on other jacks, after the work of plugging the cushion blocks by all the jacks is completed, the next step of load test is carried out by simultaneously pressurizing, and the steps are repeated until the loading is completed.
The use process of the present invention is further described below with reference to specific embodiments, which are to determine the sedimentation correction coefficient by performing a stacking test on the test platform of the present invention, perform a series of in-situ tests and deformation monitoring in a load test, and arrange 5 layered sedimentation holes, 4 deep level displacement measurement holes, and 16 surface deformation markers in each load test point. The specific process is as follows:
carrying out load test: and obtaining deformation characteristic indexes of the foundation soil body, and arranging 5 vertical displacement measuring points on the surface of the pressing plate, wherein 1 vertical displacement measuring point is arranged near the central point, and 4 vertical displacement measuring points are respectively arranged at the corners. The vertical displacement is measured by adopting an indium steel ruler and a level gauge, the indium steel ruler with the length of 2m is fixed at each measuring point, a working base point is arranged in a stable area outside the stacking area, 2 level gauges (the directions are opposite, and the data of 5 steel rulers can be observed at the same time) are erected at 30m outside the stacking area, so that the loading capacity and the displacement value of 5 displacement measuring points can be measured and read at the same time.
Secondly, layered settlement: because the soft soil foundation is extremely uneven, in order to solve the deformation condition after loading at different depths, the settlement values of the garbage soil bodies at different depths at the central position of the loading plate are monitored in the load test process, so that the settlement deformation condition of the deep part of the soil body of the foundation can be known in the stacking construction process. The depth of the layered settlement test of the load test point is 15m (2 m beyond the soft soil layer). And 1 layered settlement measuring point is arranged every 2m in the hole depth direction. The observation stage of the layered settlement comprises a loading process and an unloading process, and a pipeline is reserved to provide conditions for observing the settlement in the soil filling process in the future.
The layered settlement hole is drilled with an engineering drilling machine with the diameter of phi 127mm, a PVC high-precision inclinometer pipe with the diameter of phi 70mm is embedded in the drilled hole with the diameter of phi 110mm, settlement magnetic rings are sleeved outside the PVC high-precision inclinometer pipe at intervals of 2m and embedded in the hole with the diameter of phi 110, and sand is filled outside to be combined with the hole wall and is flushed with water to be compact.
③ deep layer displacement: a deep level displacement measuring point is arranged near the load bearing plate, so that the deformation condition of the foundation soil body in the upper load application process can be monitored, and data is provided for judging the damage mode and the lateral influence of the garbage soil. The test points are arranged on two sides of the central section of the pressing plate, 4 holes are arranged at each test point, and the distances from the test points to the edges of the pressing plate are 1m and 4m respectively; the embedding depth of the deep displacement hole of the load test point is 15m (2 m beyond the soft soil layer).
Manufacturing a deep displacement measuring hole: the inclination measuring pipe is embedded at a position 1m away from the load bearing plate, 1 hole is respectively arranged at the left and the right, an engineering drilling machine is adopted for drilling an inclination measuring hole with the diameter phi of 127mm, a PVC high-precision inclination measuring pipe with the diameter phi of 70mm is embedded in a drilling hole with the diameter phi of 110mm, and sand filled in the outer side of the inclination measuring pipe is combined with the hole wall. The inner side of the inclinometer pipe is provided with an orthogonal directional groove which is parallel or vertical to the side line of the loading plate when being buried, the buried depth of the soil body inclinometer pipe is about 15-18 m and is buried 2m below a garbage soil layer.
Surface deformation mark: surface deformation marks are buried near the periphery of the load bearing plate, the deformation condition of the surface of the soil body at the periphery of the load bearing plate in the load applying process is measured, the influence range of the load bearing plate on the peripheral soil body after the load bearing test area is stacked can be measured, 16 measuring points are arranged on the central section of the outer side of the pressing plate, 4 measuring points are arranged on each side of the periphery of the pressing plate, and the distance is 2 m.
Surface deformation marking: the burying of the ground surface monitoring points adopts a standard method of engineering measurement specification (GB50026-2007), and the ground surface monitoring points need to be buried in undisturbed soil, poured by concrete on site and protected. The steel bar is embedded in advance or is driven into the hole after the hole is drilled by a percussion drill to be used as an observation point. The top of the displacement point is marked with "+" as an observation mark. 16 monitoring points are distributed in each detection area, and a steel ruler and a level gauge are adopted for observation.
The monitoring frequency of the stratified settlement, the deep level displacement and the surface deformation target is kept consistent with the loading of the load test, the reading is carried out for 1 time after the loading is finished, and the reading is carried out once every half hour.
The loading classification is carried out according to the order of 2400kN, 3600kN, 4800kN, 6000kN, 7200kN, 8400kN, 9600kN, 10200kN, 10800kN, 11400kN and 12000kN, and is readjusted according to the deformation condition in the test.
The loading mode adopts a slow load maintaining method, namely, the loading is carried out step by step, and the next stage of load is added after the load of each stage reaches relative stability until the design requirement is reached.
The interval is 10min, 15min and 15min after each stage of loading is observed, and the settlement is measured and read every half hour later.
Sedimentation is relatively stable standard, sedimentation per hour is not more than 1.0mm, and two times of continuous stress (calculated by three continuous observations within 1.5 h) are generated, so that the stress is relatively stable and the next stage of load can be applied.
The deformation modulus E of the soft soil layer can be obtained through a P-S curve, the large-area stacking load delta P is calculated according to the stacking filler heavy weight r and the stacking height h of large-area stacking in the site, and the corresponding actually-measured settlement deformation value S' under the stacking load delta P is obtained according to the P-S curve; calculating the settlement deformation value S of the loading plate under the condition of the stacking height h by adopting a layering summation method according to the deformation modulus E of the soft soil layer, and determining the settlement correction coefficient m under the condition of the stacking height h by using S ═ Ss。
According to the method, the loads under different stacking heights h1, h2 and h3 can be respectively calculated to obtain different loads delta p1、Δp2、Δp3And obtaining corresponding settlement correction coefficient m under different loadss1、 ms2、ms3。
The method can accurately determine the settlement correction coefficient under large-area stacking load, meets the requirements of design and construction, provides reliable supporting function for settlement deformation and calculation of earth volume, and has wide engineering application prospect.
In summary, the disclosure of the present invention is not limited to the above-mentioned embodiments, and persons skilled in the art can easily set forth other embodiments within the technical teaching of the present invention, but such embodiments are included in the scope of the present invention.
Claims (7)
1. The utility model provides a dull and stereotyped load test platform of weak soil district large tracts of land which characterized in that: the test platform comprises a load bearing plate (1), a stacking platform and a plurality of loading jacks (2), wherein the load bearing plate (1) is an integrally cast-in-place reinforced concrete slab; the stacking platform comprises a steel support (3), a steel girder (4) and a steel structure platform (5), wherein the steel support (3) is erected outside the load bearing plate (1), the bottom of the steel support is provided with a reinforced concrete base (8), the plane area of the steel structure platform (5) is larger than that of the load bearing plate (1), the steel support is erected at the top of the steel support (3), reinforced concrete pad beams (6) are arranged on the contact surfaces of the steel support and the steel support (3), the steel girder (4) is welded at the position, corresponding to the load bearing plate (1), of the bottom surface of the steel structure platform (5), and the steel girder (4) is distributed at the positions of the split line or the two sides of the split line of the load bearing plate (1) symmetrically; the plurality of loading jacks (2) are uniformly distributed around the central point of the load bearing plate (1), the bottom of each loading jack (2) is arranged on the load bearing plate (1), and the top of each loading jack is connected with the steel main beam (4) in a propping manner.
2. The large-area flat plate load test platform for the weak land area according to claim 1, wherein: the load bearing plate (1) is a reinforced concrete slab with the thickness of 0.5 m-0.6 m and is provided with double layers of reinforced net sheets, the diameter of a main rib phi 18 is longitudinally and transversely arranged, and the load bearing plate (1) is provided with shear steel bars, and the strength grade of the concrete is C35.
3. The weak land area large-area flat plate load test platform of claim 1 or 2, wherein: the four loading jacks (2) are symmetrically distributed in the load carrying plate in a split line manner.
4. The weak land area large-area flat plate load test platform of claim 1 or 2, wherein: the steel structure platform (5) is a steel beam platform formed by directly adopting steel secondary beams in a crossed mode, or is a platform structure consisting of a steel beam structure formed by the steel secondary beams in a crossed mode and steel plates paved on the steel beam structure.
5. The weak land area large-area flat plate load test platform of claim 1 or 2, wherein: the steel support (3) is composed of four steel structure buttresses with the width larger than 1m, a reinforced concrete base (8) at the bottom of the steel support (3) covers clay with the thickness not smaller than 0.5m, a steel plate is embedded in the top surface of the reinforced concrete base (8), and the steel support (3) is welded on the embedded steel plate.
6. The weak land area large-area flat plate load test platform of claim 1 or 2, wherein: the weight of the stacking platform adopts a precast concrete test block (9), and the maximum loading capacity is determined to be 12000 kN.
7. The weak land area large-area flat plate load test platform of claim 1 or 2, wherein: a steel base plate (7) is embedded in the position where the loading jack (2) is installed on the load bearing plate (1).
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202121673218.5U CN215562493U (en) | 2021-07-22 | 2021-07-22 | Large-area flat plate load test platform for soft land area |
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| Application Number | Priority Date | Filing Date | Title |
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| CN202121673218.5U CN215562493U (en) | 2021-07-22 | 2021-07-22 | Large-area flat plate load test platform for soft land area |
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| CN215562493U true CN215562493U (en) | 2022-01-18 |
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| CN202121673218.5U Active CN215562493U (en) | 2021-07-22 | 2021-07-22 | Large-area flat plate load test platform for soft land area |
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