CN113123321B - Synchronous construction method for treating soft foundation by adopting compound vacuum preloading and surcharge loading - Google Patents
Synchronous construction method for treating soft foundation by adopting compound vacuum preloading and surcharge loading Download PDFInfo
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- CN113123321B CN113123321B CN201911413465.9A CN201911413465A CN113123321B CN 113123321 B CN113123321 B CN 113123321B CN 201911413465 A CN201911413465 A CN 201911413465A CN 113123321 B CN113123321 B CN 113123321B
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- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
- E02D3/00—Improving or preserving soil or rock, e.g. preserving permafrost soil
- E02D3/02—Improving by compacting
- E02D3/10—Improving by compacting by watering, draining, de-aerating or blasting, e.g. by installing sand or wick drains
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- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
- E02D27/00—Foundations as substructures
- E02D27/10—Deep foundations
- E02D27/12—Pile foundations
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- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
- E02D7/00—Methods or apparatus for placing sheet pile bulkheads, piles, mouldpipes, or other moulds
Abstract
The invention discloses a soft foundation treatment and pile foundation synchronous construction method, which comprises the following steps: leveling the field and confirming a soft foundation area (3); dividing a construction area outside the soft foundation area (3) into a construction area (2) with a strong influence range and a construction area (1) with a weak influence range; a pile machine is arranged on the weak influence range construction area (1), a soil body side shift monitoring point (4) is arranged on the strong influence range construction area (2), and a vacuum preloading system is arranged in the soft foundation area (3); when the pile foundation construction of the weak influence range construction area (1) is carried out, a vacuum preloading system is adopted to carry out soft foundation treatment on the soft foundation area (3); completing pile foundation construction and reaching the design requirement area, and constructing a bottom plate; when the pile foundation construction and the soft foundation treatment simultaneously meet the design requirements, the first layer of pile loading in the soft foundation area (3) starts to be constructed; when the bottom plate meets the design requirement, the soft foundation area (3) at the joint of the bottom plate is firstly subjected to second layer stacking construction until the last layer stacking is completed.
Description
Technical Field
The invention belongs to the technical field of construction of constructional engineering, and particularly relates to a method for synchronously constructing a pile foundation by combining compound vacuum preloading soft foundation treatment with pile loading.
Background
The soft foundation treatment is a process of treating a soft foundation to ensure that the settlement of the soft foundation is firm enough and the consolidation degree and the stability of the soft foundation are improved to meet the design requirements in order to prevent accidents such as unstable buildings and the like caused by the fact that the foundation sinks and cracks after the construction if the foundation is not firm enough before the construction.
With the continuous development of economy in coastal areas, the increase of factory buildings, ports, airports, highways and residential buildings, the treatment and the use of soft soil foundations become more and more extensive; because the bearing capacity of the soft soil is low, the deformation after construction is large, the consolidation settlement time is long, and the requirements of engineering can not be met, the treatment of the soft soil foundation is the focus of the foundation treatment attention in coastal areas all the time; at present, the soft soil foundation treatment methods are many, and can be divided into a drainage consolidation method (a preloading method, a vacuum preloading method and a combined preloading method), a composite foundation method and the like according to the foundation treatment and consolidation principle.
At present, compound vacuum preloading combined loading soft foundation treatment is carried out at home, pile foundation construction is carried out after soil is stabilized, the construction method needs to be divided into two stages of soft foundation treatment and pile foundation construction, and construction period is long.
The above problems are urgently needed to be improved and to be solved.
Disclosure of Invention
In order to overcome the defects of the prior art, a method for synchronously constructing the pile foundation and the soft foundation treatment by combining compound vacuum preloading and pile loading is provided.
The technical scheme adopted by the invention is as follows: the method for synchronous construction of pile foundation and soft foundation treatment by adopting compound vacuum preloading and pile loading comprises the following steps:
s1, leveling a field, and confirming a soft foundation area;
s2, dividing a construction area outside the soft foundation area into a construction area with a strong influence area and a construction area with a weak influence area according to the influence area of the soft foundation treatment on the peripheral soil body, and marking the construction areas;
s3, arranging a pile machine on the construction area with the weak influence range, arranging soil body side shift monitoring points on the construction area with the strong influence range, and arranging a vacuum preloading system in the soft foundation area;
s4, performing soft foundation treatment on the soft foundation area by adopting a vacuum preloading system while constructing the pile foundation in the weak influence area construction area;
s5, completing pile foundation construction and reaching a design requirement area, and starting construction of a bottom plate;
s6, when pile foundation construction and soft foundation treatment are completed and design requirements are met simultaneously, construction is started on the first layer of pile load in the soft foundation area;
and S7, when the bottom plate is finished and meets the design requirement, the soft foundation area at the joint of the bottom plate is firstly subjected to second layer stacking construction until the last layer stacking is finished.
Preferably, in step S1, the soft foundation area range is confirmed according to a design drawing.
Wherein the soft foundation area is a range which needs foundation treatment and is marked in a design drawing by a designer according to a geological survey report.
Preferably, in the step S2, the influence range of the soft foundation treatment on the soil body is confirmed, firstly, the pile foundation is subjected to crack and deflection control calculation according to the normal use limit state of the pile foundation, and the lateral allowable deformation value Δ L of the pile foundation is obtained 0 Then establishing a finite element model, and calculating the maximum lateral deformation accumulated value L of the soil body at the foundation pile position of each row of piles through simulation i Outside the soft foundation region (3), Δ L 0 ≤L i Part is set as a construction area with a strong influence range, delta L 0 ＞L i And setting the part as a construction area with a weak influence range.
In the soft foundation treatment process, adverse effects can be caused to the surrounding soil body, such as soil foundation loosening, sinking and the like, and the buildings on the soil body are naturally damaged to a certain extent; before the soft foundation treatment, the influence range of the soil body is determined, and three construction areas are divided according to the influence range of the soft foundation treatment on the soil body.
Preferably, in the step S3, the soil body side shift monitoring points in the construction area with the strong influence range are expanded by 10 to 50m from the foundation treatment boundary, one soil body side shift monitoring point is radially arranged every 5m, the number of the soil body side shift monitoring points in the radial direction is taken as a group, and the number of the groups uniformly arranged in the circumferential direction is determined according to the construction drawing and the monitoring range.
Preferably, in the step S3, a plurality of pile machines are circumferentially and uniformly arranged in the construction area with the weak influence range, and the vacuum preloading system performs construction according to a design drawing.
The determination of the number of the pile machines needs to be determined according to factors such as the number of the pile machines in the drawing, the construction progress of the pile machines, the soft foundation processing time and the like.
Preferably, in the step S4, the pile foundation is constructed from the outside of the weak influence range construction area (1) to the inside, the finite element model is corrected according to the monitoring data to obtain a time axis graph of the pile position soil lateral deformation accumulated value of the strong influence range construction area, and the maximum value L of the pile position soil lateral deformation accumulated value of the pile foundation is calculated i Subtracting pile foundation lateral allowable deformation value delta L 0 To give L' i And obtaining a construction time node by the corresponding relation between the pile position soil body lateral deformation accumulated value and the time axis curve graph so as to judge whether the pile foundation can be constructed.
Preferably, when the pile foundation construction in the step S5 is completed and reaches more than 80% of the designed strength value, the bottom plate starts block construction.
Preferably, in the step S6, the pile foundation engineering is completed and reaches more than 80% of design strength, and after the vacuum preloading system runs fully for 30d, the soft foundation region first sand cushion layer stacking construction starts, and the vacuum preloading system keeps running fully at the same time.
Wherein the first sand bedding layer is piled with the loading thickness of 1m.
Preferably, the first layer and the subsequent stacking construction are constructed by spreading the soft foundation region from the center to the periphery.
The first layer of stacking construction is paved from the center to the periphery and is constructed by the bottom plate in blocks, and normal construction of other machines is not hindered by adopting the construction scheme, so that the construction site is well-ordered.
Preferably, in step S7, when the floor finish block reaches more than 80% of the design strength value, the soft foundation area at the joint with the floor is subjected to the second layer stacking construction first until the last layer stacking is finished.
The invention has the beneficial effects that: according to the method for synchronously constructing the composite vacuum preloading combined preloading soft foundation treatment and the pile foundation engineering, the three construction areas are divided, the vacuum preloading system is arranged in the soft foundation area, and the pile machine is arranged in the non-soft foundation area, so that the pile foundation construction and the soft foundation treatment are simultaneously carried out, and the problem of long construction period of the pile foundation engineering construction after the composite vacuum preloading combined preloading soft foundation treatment is firstly constructed is solved; the construction method adopts the bottom plate to carry out block construction, and sets the sequence of pile foundation and pile loading construction, so that the construction process arrangement is scientific and reasonable, the construction period is greatly shortened, and the soft foundation treatment effect and the pile foundation engineering quality are ensured.
Drawings
FIG. 1 is a construction area division diagram of the method for synchronous construction of pile foundation and soft foundation treatment by combining compound vacuum preloading;
fig. 2 is a construction floor plan view of fig. 1.
In the figure: 1-weak influence range construction area 2-strong influence range construction area 3-soft foundation area 4-soil body side shift monitoring point.
Detailed Description
The invention is further described below with reference to the specific drawings.
As shown in fig. 1 and 2, the method for synchronous construction of soft foundation treatment and pile foundation by adopting compound vacuum preloading and surcharge loading comprises the following steps:
s1, firstly, lofting and confirming a construction area according to a design drawing, dividing the area by using color flags or other markers, then carrying out leveling treatment on the construction area by using a digging machine, and then marking the area by using the color flags or other markers according to a soft foundation area 3 confirmed by the design drawing. .
S2, the soft foundation treatment can cause damage to surrounding soil bodies in different degrees, and the pile foundation is subjected to crack and deflection control calculation according to the normal use limit state of the pile foundation to obtain the lateral allowable deformation value delta L of the pile foundation 0 Then establishing a finite element model, and calculating the maximum lateral deformation accumulated value L of the soil body at the foundation pile position of each row of piles through simulation i Outside the soft foundation region (3), Δ L 0 ≤L i Set as the construction area 2, delta L with strong influence range 0 ＞L i Part is set to weakAnd (3) constructing the area 1 within the influence range, dividing the area by using color flags or other markers, wherein the dividing line can be used as a reference line of the construction area, so that the construction becomes well-ordered.
S3, after the construction area is divided, determining that 32 required pile machines are needed, arranging mechanical approaches of the pile machines, a vacuum preloading system and the like, uniformly arranging the pile machines in the radial direction according to the outermost circle of the construction area 1 with a weak influence range, simultaneously sequentially installing instruments such as a sand cushion layer, a drainage plate, a pipe network and the like on the soft foundation area 3 by the vacuum preloading system, arranging soil body side shift monitoring points 4 in the construction area 2 with a strong influence range according to a construction drawing and a monitoring range, expanding the soil body side shift monitoring points 20m from the boundary of the soft foundation area 3, respectively arranging one soil body side shift monitoring point 4 at intervals of 5m in the radial direction, and uniformly arranging 12 groups in the circumferential direction by taking the number of the radial 5 soil body side shift monitoring points 4 as a group (see fig. 2).
And S4, the pile foundation starts to be constructed inwards from the outer side of the weak influence range construction area 1, meanwhile, after the vacuum preloading system is installed in the soft foundation area 3, the vacuum preloading system is vacuumized to 0.06MPa in advance to check whether the vacuum tube leaks air, if no problem exists, the vacuum degree is increased to be more than 0.087MPa in full-load operation, and meanwhile, the pile foundation construction in the strong influence range construction area 2 is organized according to data measured by soil body lateral movement monitoring points 4.
S5, when the whole construction of the pile foundation in the weak influence range construction area 1 and the strong influence range construction area 2 is completed, and the detection is carried out through the pile foundation strength, when the pile foundation strength is detected to reach more than 80% of design strength value, the excavator begins to excavate the area meeting the design requirement, then the partition blocks reasonably and satisfactorily are carried out on the bottom plate through the post-cast strip, then according to construction drawings and a construction scheme, the bottom plate construction is carried out according to the blocks, the bottom plate adopts block construction, the labor force can be effectively reduced, the labor efficiency is improved, the construction collision is avoided, and the construction period is greatly shortened.
And S6, when the pile foundation meets the condition of the step S5 and the vacuum preloading is carried out for 30d, the first layer of stacking load of the soft foundation area 3 begins to spread from the center to the periphery for construction, and the first layer of stacking load adopts a sand cushion layer with the thickness of 1m.
S7, when the bottom plate finishes that the block reaches more than 80% of the design strength value, the soft foundation area 3 at the joint of the bottom plate of the block is firstly subjected to second layer stacking construction until the last layer stacking is finished.
Claims (8)
1. The method for synchronous construction of pile foundation and soft foundation treatment by adopting compound vacuum preloading and pile loading is characterized by comprising the following steps of: the method comprises the following steps:
s1, leveling a field, and confirming a soft foundation area (3);
s2, dividing a construction area outside the soft foundation area (3) into a strong influence area construction area (2) and a weak influence area construction area (1) according to the influence area of the soft foundation treatment on the peripheral soil body, and marking the construction areas;
wherein: confirming the influence range of the soft foundation treatment on the soil body, firstly carrying out crack and deflection control calculation on the pile foundation according to the normal use limit state of the pile foundation to obtain the lateral allowable deformation value delta L0 of the pile foundation, then establishing a finite element model, calculating the maximum lateral deformation accumulated value Li of the soil body at the pile foundation position of each row of piles through simulation, setting the part, outside the soft foundation area (3), of the part, with the value being more than or equal to delta L0, as a strong influence range construction area (2), and setting the part, with the value being more than or equal to delta L0, as a weak influence range construction area (1);
s3, arranging a pile machine on the weak influence range construction area (1), arranging soil body side shift monitoring points (4) on the strong influence range construction area (2), and arranging a vacuum preloading system in the soft foundation area (3); wherein: soil body side shift monitoring points (4) are expanded by 20m from the boundary of the soft foundation area (3), one soil body side shift monitoring point (4) is respectively arranged at every 5m in the radial direction, and 12 groups are uniformly arranged in the circumferential direction by taking the number of the radial 5 soil body side shift monitoring points (4) as a group;
s4, performing soft foundation treatment on the soft foundation area (3) by adopting a vacuum preloading system while constructing the pile foundation in the weak influence area construction area (1);
s5, completing pile foundation construction and reaching a design required area, and starting construction of the base plate;
s6, when pile foundation construction and soft foundation treatment are completed and design requirements are met simultaneously, construction is started on the first layer of stacking load in the soft foundation area (3);
and S7, when the bottom plate is finished and meets the design requirement, the soft foundation area (3) at the joint of the bottom plate is firstly subjected to second layer stacking construction until the last layer stacking is finished.
2. The method for synchronous construction of soft foundation treatment and pile foundation by adopting compound vacuum preloading and pile loading as claimed in claim 1, wherein: in the step S1, the range of the soft foundation area (3) is confirmed according to a design drawing.
3. The method for synchronous construction of soft foundation treatment and pile foundation by adopting compound vacuum preloading and pile loading as claimed in claim 1, wherein: in the step S3, a plurality of pile machines are uniformly arranged in the construction area (1) with the weak influence range annularly, and the vacuum preloading system is used for construction according to a design drawing.
4. The method for synchronous construction of soft foundation treatment and pile foundation by adopting compound vacuum preloading and pile loading as claimed in claim 1, wherein: in the step S4, the pile foundation is constructed from the outer side of the weak influence range construction area (1) to the inner side, meanwhile, the finite element model is corrected according to the monitoring data, a curve graph of the pile position soil body lateral deformation accumulated value and the time axis of the strong influence range construction area (2) is obtained, and the maximum value L of the pile position soil body lateral deformation accumulated value of the pile foundation is used i Subtracting pile foundation lateral allowable deformation value delta L 0 To obtain L ‘ i And correspondingly obtaining construction time nodes by the pile position soil body lateral deformation accumulated value and the time axis curve graph so as to judge whether the pile foundation can be constructed or not.
5. The method for synchronous construction of soft foundation treatment and pile foundation by adopting compound vacuum preloading and surcharge loading according to claim 1, wherein: and in the step S5, when the pile foundation construction is finished and the design strength value reaches more than 80%, the base plate starts block construction according to the post-cast strip.
6. The method for synchronous construction of soft foundation treatment and pile foundation by adopting compound vacuum preloading and pile loading as claimed in claim 1, wherein: in the step S6, the pile foundation engineering is completed and reaches more than 80% of design strength, and after the vacuum preloading system runs for 30d in full load, the first sand cushion layer stacking construction of the soft foundation area (3) begins, and the vacuum preloading system keeps running in full load at the same time.
7. The method for synchronous construction of soft foundation treatment and pile foundation by adopting compound vacuum preloading and pile loading as claimed in claim 6, wherein: and the first layer and the subsequent stacking construction are paved from the center of the soft foundation area (3) to the periphery.
8. The method for synchronous construction of soft foundation treatment and pile foundation by adopting compound vacuum preloading and pile loading as claimed in claim 1, wherein: in the step S7, when the floor finish block reaches more than 80% of the design strength value, the soft foundation area (3) connected with the floor is firstly subjected to second layer stacking construction until the last layer stacking is finished.
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Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2005207164A (en) * | 2004-01-26 | 2005-08-04 | Maruyama Kogyo Kk | Soil improvement method for weak ground, and filled structure prepared by using the method |
| CN103225267A (en) * | 2013-03-29 | 2013-07-31 | 天津二十冶建设有限公司 | Construction method of deep and thick soft soil foundation bed bridge abutment |
| CN106049412A (en) * | 2016-07-02 | 2016-10-26 | 天鸿建设集团有限公司 | Construction method of heaping pre-compression soft foundation reinforcement |
| CN208815506U (en) * | 2018-08-02 | 2019-05-03 | 陈淑青 | A kind of soft base joint preloading structure |
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2019
- 2019-12-31 CN CN201911413465.9A patent/CN113123321B/en active Active
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2005207164A (en) * | 2004-01-26 | 2005-08-04 | Maruyama Kogyo Kk | Soil improvement method for weak ground, and filled structure prepared by using the method |
| CN103225267A (en) * | 2013-03-29 | 2013-07-31 | 天津二十冶建设有限公司 | Construction method of deep and thick soft soil foundation bed bridge abutment |
| CN106049412A (en) * | 2016-07-02 | 2016-10-26 | 天鸿建设集团有限公司 | Construction method of heaping pre-compression soft foundation reinforcement |
| CN208815506U (en) * | 2018-08-02 | 2019-05-03 | 陈淑青 | A kind of soft base joint preloading structure |
Non-Patent Citations (1)
| Title |
|---|
| 李树奇等.潮差带地区水下真空预压加固软基技术.《工程排水与加固技术理论与实践—第八届全国工程排水与加固技术研讨会论文集》.2011, * |
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