CN106320398A - Loess gully area bridge substructure effect identification method - Google Patents
Loess gully area bridge substructure effect identification method Download PDFInfo
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- CN106320398A CN106320398A CN201610911238.9A CN201610911238A CN106320398A CN 106320398 A CN106320398 A CN 106320398A CN 201610911238 A CN201610911238 A CN 201610911238A CN 106320398 A CN106320398 A CN 106320398A
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- pile
- reinforcing rib
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- loess
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- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
- E02D33/00—Testing foundations or foundation structures
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Abstract
The invention discloses a loess gully area bridge substructure effect identification method. The method comprises the following steps that firstly, in the construction stage of drilling and pile grouting of a loess gully area bridge substructure, a plurality of pairs of calibration reinforcement meters are installed in set positions of different depths of a reinforcement cage along the pile length; after bridge forming, tested reinforcement internal force of different sections of a pile foundation is obtained according to frequencies output by the reinforcement meters, and corresponding reinforcement strain is obtained through the reinforcement internal force and is the pile body concrete strain; and the maximum pile body bending moment and the position are indentified through the bending moment distribution along a pile body after different-degree erosion damage to a loess slope, the acting point of resultant force of the pile side soil pressure is judged, and on the basis, security state evaluation of the loess gully area bridge substructure is conducted. The loess gully area bridge substructure effect identification method is simple to operate and small in test result error, the bearing capability and risk evolution law of the pile foundation under special geological conditions after bridge forming can be reflected really, and the tested results can provide scientific methods and basis for later management, maintenance and reinforcement of the bridge substructure.
Description
Technical field
The present invention relates to bridge section model field, it particularly relates to a kind of loessial gulch district bridge substructure
Effect recognition methods.
Background technology
Being in innerland, Canal in Loess Area and use the Bridges in Mountainous Areas of standard span, due to the steep ditch depth in slope, loess gully area, it is single
Row's queen post substructure often presents following characteristics: 1. bridge pier is laid along massif height, the side slope of bridge pier platform be high abrupt slope very
The highest steep slope；2. soft rock-soil near pile foundation is easily washed away in operation phase bridge floor central drainage；3. near soil erosion or pile foundation
Ground avalanche causes effective length not enough.Loess formation porous, water penetration, depression are relatively strong, harder when dry, once flowing water
Soak, easily peel off and corroded, even subside；Such as heavy showers, under the washing away of mountain torrents and highway central drainage,
The bridge lower periphery soil body may be caused to peel off, subside, bring serious potential safety hazard to substructure.
In view of These characteristics, loess gully the area often soil erosion of generation, slope body landing are to Bridges in Mountainous Areas substructure
The impact of stability and bearing capacity of pile foundation is fairly obvious.The geological disasters such as the landslide of seasonal periodicity, mud-rock flow are to substructure
Cause direct impact failure especially.
Therefore, necessary loess slope erosion damage in various degree after bridge is detected into and bridge substructure bearing characters
And safe condition.The problems referred to above of prior art are needed badly and are had been resolved.
Summary of the invention
The technical problem to be solved is to solve into loess slope erosion damage in various degree after bridge and under bridge
The problem that portion's structural bearing character and safe condition cannot judge.
In order to solve above-mentioned technical problem, the technical solution adopted in the present invention is to provide under a kind of loessial gulch district bridge
Portion's structure effect recognition methods, it is characterised in that the method comprises the following steps:
(1) when loessial gulch district bridge substructure drilling pouring stake is constructed, long set at steel reinforcement cage different depth along stake
Position in two separate ranks connect fixed installation some to reinforcing rib meter；
Single queen post bridge substructure is made up of bridge pier, straining beam and pile foundation, long often along stake on pile foundation steel bar cage
Installing a pair reinforcing rib meter across a certain distance, stake length direction reinforcing rib meter installing space can require to adjust with measuring accuracy；At reinforcing bar
During meter is installed, loessial gulch district side slope is the most intact；
(2) after becoming bridge operation, natural frequency of vibration f of collection in worksite reinforcing rib meter1、f2, and directly obtain pile foundation different depth
Reinforcing bar axle power P1、P2；
Being carried out data acquisition by data collecting instrument and connecting line, reinforcing rib meter is before use between stress and the natural frequency of vibration
Linear relationship is demarcated, linear calibration's relation directly obtain reinforcing bar axle power P1、P2；
(3) the axial strain ε of pile foundation arbitrary section test reinforcing bar1、ε2By εi=Pi/EgAgDirectly obtain, EgFor reinforcing bar
Elastic modelling quantity, AgFor testing the cross-sectional area of reinforcing bar, reinforcing bar and pile concrete compatible deformation, the axial strain ε of reinforcing bar1、ε2I.e.
The concrete strain ε at pile foundation respective cross-section edge1、ε2；
(4) by the concrete axial of two the reinforcing rib meter measuring points in same cross section to strain stress1、ε2Difference try to achieve the arbitrary cross section of pile foundation
Bending strain △ ε；
(5) moment M suffered by the arbitrary cross section of pile body is by M=EI △ ε/b0Obtain, b0For the spacing of 2 reinforcing rib meters in arbitrary cross section,
E is the composite modulus in pile body cross section, and I is pile body cross section centering equatorial moment of inertia, thus obtains stake after loess slope erosion damage
Body Bending moment distribution, is identified maximal bending moment and position by bending distribution.
Further, in described step (1), two row reinforcing rib meters are positioned at soil lateral pressure and apply on direction in pile body cross section,
Lay respectively at the two ends of same diameter；In described step (2), reinforcing rib meter is before use to reinforcing rib meter stress and reinforcing rib meter output frequency
Linear relationship between rate is demarcated；
Further, in described step (5), pile body maximal bending moment position is soil pressure against piles after loess slope erosion damage
Effect Resultant force position.
Further, in described step (5), pile body maximal bending moment position is positioned at pile foundation cracking after loess slope erosion damage
Near Chu.
Further, in described step (5), by identifying that position occurs in pile body maximal bending moment, it is possible to judge loess limit
Slope erosion damage degree and the safe condition of bridge substructure.
The method of the present invention is simple to operate, test result error is little, it is possible to reflect into special geologic condition after bridge really
The load-carrying properties of lower pile foundation and risk development law, it addition, test result can be pipe of single queen post bridge substructure later stage
Support and maintenance and reinforcement provides scientific method and foundation.
Accompanying drawing explanation
Fig. 1 is loessial gulch district bridge substructure effect identification system layout.
Fig. 2 is for becoming loess slope erosion damage synoptic chart after bridge.
Fig. 3 is pile body cross section reinforcing rib meter installation site schematic diagram.
Fig. 4 is single queen post bridge substructure schematic diagram.
Fig. 5 is loessial gulch district bridge substructure effect recognition result.
Detailed description of the invention
Below by specific embodiment, the invention will be further described, and following example are illustrative, is not limit
Qualitatively, it is impossible to limit protection scope of the present invention with this.
As shown in Fig. 1～Fig. 5, the present invention provides a kind of loessial gulch district bridge substructure effect recognition methods, including
Following steps:
(1) when loessial gulch district bridge substructure drilling pouring stake 4 is constructed, long at steel reinforcement cage 3 different depth both along stake
Location the place of putting in two separate ranks connect fixedly mount some to reinforcing rib meter 1,2, as shown in Figure 3；
Single queen post bridge substructure is made up of bridge pier 6, straining beam 5 and pile foundation 4, such as Fig. 4, at pile foundation 4 steel reinforcement cage 3
On along stake is long, a pair reinforcing rib meter 1,2 is installed at spacing intervals, stake length direction reinforcing rib meter installing space can be with measuring accuracy requirement
Adjusting, reinforcing rib meter 1,2 mounting arrangements is specifically shown in Fig. 1, Fig. 3, and during reinforcing rib meter 1,2 is installed, loessial gulch district side slope 9 is basic
Intact；
(2) after becoming bridge operation, natural frequency of vibration f of collection in worksite reinforcing rib meter 1,21、f2, and it is different deep to directly obtain pile foundation 4
Reinforcing bar 3 axle power P of degree1、P2；
Changing loessial gulch side slope 9 pre-existing topography geomorphologic conditions after becoming bridge operation, after slope erosion destroys, overview is such as schemed
2, data collecting instrument 7 and connecting line 8 carry out data acquisition, reinforcing rib meter 1,2 is before use between stress and output frequency
Linear relationship is demarcated, linear calibration's relation directly obtain reinforcing bar 3 axle power P1、P2；
(3) the axial strain ε of pile foundation 4 arbitrary section test reinforcing bar 31、ε2By εi=Pi/EgAgDirectly obtain, EgFor reinforcing bar 3
Elastic modelling quantity, AgFor testing the cross-sectional area of reinforcing bar 3, reinforcing bar 3 and pile concrete compatible deformation, the axial strain of reinforcing bar 3
ε1、ε2The i.e. concrete strain ε at pile foundation 4 respective cross-section edge1、ε2；
(4) by the concrete axial of two, same cross section reinforcing rib meter 1,2 measuring point to strain stress1、ε2Difference to try to achieve pile foundation 4 arbitrary
The bending strain △ ε in cross section；
(5) moment M suffered by the arbitrary cross section of pile body 4 is by M=EI △ ε/b0Obtain, b0For 2, arbitrary cross section reinforcing rib meter 1,2
Spacing, E is the composite modulus in pile body 4 cross section, and I is pile body 4 cross section centering equatorial moment of inertia, thus obtains loess slope and washes away brokenly
Pile body 4 Bending moment distribution after Huai, is identified maximal bending moment and position by pile body 4 Bending moment distribution.
In such scheme, in described step (1), 2 row reinforcing rib meters are positioned at soil lateral pressure and apply on direction in pile body cross section,
Lay respectively at the two ends of same diameter；In described step (2), reinforcing rib meter is before use to reinforcing rib meter stress and reinforcing rib meter output frequency
Linear relationship between rate is demarcated；In described step (5), pile body maximal bending moment position is stake after loess slope erosion damage
Lateral earth pressure effect Resultant force position；In described step (5), pile body maximal bending moment position is positioned at stake after loess slope erosion damage
Near at base cracking；In described step (5), by identifying that position occurs in pile body maximal bending moment, it is possible to judge that loess slope rushes
Brush destructiveness and the safe condition of bridge substructure.
The present invention apply specific embodiment principle and the embodiment of the present invention are set forth, above example
Method and the core concept thereof being only intended to help to understand the present invention is described, one of ordinary skill in the art is not being done
Go out the every other embodiment obtained under creative work premise, broadly fall into the scope of the protection of the present invention.
Claims (5)
1. a loessial gulch district bridge substructure effect recognition methods, it is characterised in that the method comprises the following steps:
(1) when loessial gulch district bridge substructure drilling pouring stake is constructed, long at steel reinforcement cage different depth commitment positions along stake
Place's series connection fixed installation in two separate ranks is some to reinforcing rib meter；
Single queen post bridge substructure is made up of bridge pier, straining beam and pile foundation, long every one along stake on pile foundation steel bar cage
Determining deviation installs a pair reinforcing rib meter, and stake length direction reinforcing rib meter installing space can require to adjust with measuring accuracy；Pacify at reinforcing rib meter
During dress, loessial gulch district side slope is the most intact；
(2) after becoming bridge operation, natural frequency of vibration f of collection in worksite reinforcing rib meter1、f2, and directly obtain the reinforcing bar of pile foundation different depth
Axle power P1、P2；
Data acquisition is carried out, reinforcing rib meter linear between stress and the natural frequency of vibration before use by data collecting instrument and connecting line
Relation is demarcated, linear calibration's relation directly obtain reinforcing bar axle power P1、P2；
(3) the axial strain ε of pile foundation arbitrary section test reinforcing bar1、ε2By εi=Pi/EgAgDirectly obtain, EgSpringform for reinforcing bar
Amount, AgFor testing the cross-sectional area of reinforcing bar, reinforcing bar and pile concrete compatible deformation, the axial strain ε of reinforcing bar1、ε2I.e. pile foundation phase
Answer the concrete strain ε of section edges1、ε2；
(4) by the concrete axial of two the reinforcing rib meter measuring points in same cross section to strain stress1、ε2Difference try to achieve the curved of the arbitrary cross section of pile foundation
Curved strain △ ε；
(5) moment M suffered by the arbitrary cross section of pile body is by M=EI △ ε/b0Obtain, b0For the spacing of 2 reinforcing rib meters in arbitrary cross section, E is
The composite modulus in pile body cross section, I is pile body cross section centering equatorial moment of inertia, and after thus obtaining loess slope erosion damage, pile body is curved
Square is distributed, bending distribution identify maximal bending moment and position.
2. the method for claim 1, it is characterised in that in described step (1), two row reinforcing rib meters are positioned in pile body cross section
Soil lateral pressure applies, on direction, to lay respectively at the two ends of same diameter；In described step (2), reinforcing rib meter is before use to steel
Linear relationship between muscle meter stress and reinforcing rib meter output frequency is demarcated.
3. the method for claim 1, it is characterised in that in described step (5), pile body maximal bending moment position is loess limit
Soil pressure against piles effect Resultant force position after the erosion damage of slope.
4. the method for claim 1, it is characterised in that in described step (5), pile body maximal bending moment position is positioned at loess
Slope erosion destroy after at pile foundation cracking near.
5. the method as described in claim 3 or 4, it is characterised in that in described step (5), by identifying pile body maximal bending moment
Position occurs, it is possible to judge loess slope erosion damage degree and the safe condition of bridge substructure.
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| CN201610911238.9A CN106320398A (en) | 2016-10-19 | 2016-10-19 | Loess gully area bridge substructure effect identification method |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107988894A (en) * | 2017-08-31 | 2018-05-04 | 中铁二院工程集团有限责任公司 | The concrete buttress structure for preventing high gradient slope bridge pier from deviating |
| CN108009363A (en) * | 2017-12-04 | 2018-05-08 | 中铁二院工程集团有限责任公司 | A kind of mud-rock flow washes away the computational methods of bridge pier |
| CN112012251A (en) * | 2020-08-27 | 2020-12-01 | 河北工业大学 | FBG system-based combined monitoring method for axial-bending deformation of inclined PHC square pile |
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| KR100914058B1 (en) * | 2008-04-24 | 2009-08-28 | 백규호 | Static loading apparatus for pile load test with removable forcing device and its testing method thereof |
| CN104895126A (en) * | 2015-06-19 | 2015-09-09 | 河海大学 | Model pile body internal force rating device and method |
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2016
- 2016-10-19 CN CN201610911238.9A patent/CN106320398A/en active Pending
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR100914058B1 (en) * | 2008-04-24 | 2009-08-28 | 백규호 | Static loading apparatus for pile load test with removable forcing device and its testing method thereof |
| CN104895126A (en) * | 2015-06-19 | 2015-09-09 | 河海大学 | Model pile body internal force rating device and method |
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Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107988894A (en) * | 2017-08-31 | 2018-05-04 | 中铁二院工程集团有限责任公司 | The concrete buttress structure for preventing high gradient slope bridge pier from deviating |
| CN107988894B (en) * | 2017-08-31 | 2023-07-18 | 中铁二院工程集团有限责任公司 | Concrete buttress structure for preventing high-steep slope pier from shifting |
| CN108009363A (en) * | 2017-12-04 | 2018-05-08 | 中铁二院工程集团有限责任公司 | A kind of mud-rock flow washes away the computational methods of bridge pier |
| CN108009363B (en) * | 2017-12-04 | 2021-02-02 | 中铁二院工程集团有限责任公司 | Calculation method for scouring bridge piers by debris flow |
| CN112012251A (en) * | 2020-08-27 | 2020-12-01 | 河北工业大学 | FBG system-based combined monitoring method for axial-bending deformation of inclined PHC square pile |
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Application publication date: 20170111 |