CN1114377A

CN1114377A - Method for burying strain gauge set in rolled concrete

Info

Publication number: CN1114377A
Application number: CN 94111525
Authority: CN
Inventors: 杨立新; 王志远
Original assignee: NANJING INST OF AUTOMATION MINISTRY OF ELECTRIC POWER INDUSTRY
Current assignee: NANJING INST OF AUTOMATION MINISTRY OF ELECTRIC POWER INDUSTRY
Priority date: 1994-12-15
Filing date: 1994-12-15
Publication date: 1996-01-03
Anticipated expiration: 2014-12-15
Also published as: CN1047422C

Abstract

The method for burying strain gage group in rolled concrete features that a group of strain gages is arranged upside down, digging and drilling are combined for burying, and the instruments are inversely in drilled holes. Its advantages include little deformation of instrument, high reliability and reducing volume of earthwork for excaving and filling.

Description

A kind of in roller compacted concrete the method for burying strain gauge set

The present invention relates to the new method of relevant monitoring technology, particularly a kind of burying strain gauge set in the roller compacted concrete engineering technology.

Constructing the technology that engineering for example builds a dam with roller compacted concrete is the eighties new developing technology, because it has advantages such as speed of application is fast, construction costs is low, structural reliability is good, has broad prospects in water power is built.China's Three Gorges Projects have determined to adopt this technology to build a dam.Prototype measurement is the important means of this new technology of building a dam of research and development, and using in groups, strain meter carries out the essential important component that stress monitoring is a dam safety monitoring to RCCD (Roller Compacted Concrete Dam).Owing to have vibroroller cmpacting successively during Construction of Rolled Concrete Dam, do not see so far both at home and abroad to have and successfully bury the example of strain meter in groups in enormous quantities therein underground.Therefore, RCCD (Roller Compacted Concrete Dam) is still unresolved so far with the problem that strain meter in groups carries out safety monitoring.Domesticly in several RCCD (Roller Compacted Concrete Dam) engineerings, carried out some and buried the useful trial of monitoring instrument underground.Basic skills has two kinds, digs pit to bury method underground and method is buried in boring underground, below narration respectively.1, dig pit and bury method underground, the layer of concrete at instrument cloth point height place roll qualified after, dig pit again or slot embedded instrument.The size of digging pit is decided by the instrument volume.Identical with method for embedding in conventional concrete, need to reject the big aggregate of particle diameter greater than 8cm, bury the concrete that the back backfill is dug out underground, then according to certain rules manual zoning's compacting.It is feasible that this method is applied to single testers such as thermometer, osmometer, single strain meter, but big in groups strain meter is buried the comparison difficulty underground with this method.Main cause is that strain meter is multi-faceted in groups, volume is big, and according to existing observation standard in groups strain meter should be fixed on bearing pole and go up integral body and bury underground, the volume of need digging pit is excessive, need bury the five hole volumes of burying underground to Strain Meter Set (DI-25) usually underground and be about long * wide * dark=120 * 80 * 85cm ³, the excavation and filling workload is all bigger, and big, the time-consuming length of embedded instrument difficulty all can impact the quality and the programming of continuous roller compaction construction.If using small strain meter group (DI-10) accuracy of observation instead is reduced to about 60% of big Strain Meter Set, do not meet the observation requirement; If the bearing pole of cancellation Strain Meter Set, the position of instrument embedding and direction are difficult to guarantee.Fig. 1 buries the five exemplary configurations modes to Strain Meter Set underground for digging pit in conventional concrete.6 is Strain Meter Set bearing pole among the figure, 5 for vertically to strain meter, 4,8 is the 45 strain meter, 3 is that level is to strain meter, another level, is not drawn among the figure in 3 vertical direction to strain meter, and 7 is cable, and 9 are the location anchor pole, 1 is protecting formwork, and 10 is concrete, and 2 for digging pit.2, method is buried in boring underground, layer of concrete roll qualified after, positioning and directing boring, can get out vertically to or the hole of 45, single tester is imbedded Kong Zhonghou, backfill expansive cement mortar in the hole.This method is the most suitable bury underground vertically to list prop up instrument such as thermometer, unidirectional strain meter etc., but can not bury multidirectional strain meter in groups underground, because it can't take into account the instrument embedding of vertical plane and horizontal plane simultaneously with bearing pole.

The objective of the invention is, provide a kind of in roller compacted concrete the method for successful burying strain gauge set, make in groups strain meter in the RCCD (Roller Compacted Concrete Dam) safety monitoring, bring into play its due effect.

The major technique feature of the inventive method is: (1) will be in groups strain meter be inverted to lay and bury underground; (2) adopt the method for embedding dig pit, hole and combine, dig small-sized positioning pit earlier, again in the positioning pit internal drilling, the instrument in the vertical plane is buried underground with boring method, the instrument in the horizontal plane is buried underground with the method for digging pit; (3) in groups in the strain meter instrument in the vertical plane oppositely insert in the boring, the instrument lead exit is connected with the bearing strut fixation by reverse joint.Specifically: the inventive method realizes as follows:

(1) instrument position of living in layer of concrete roll qualified after, dig a small-sized positioning pit, the volume in hole is as the criterion with instrument in the horizontal plane that can hold strain meter in groups slightly well-to-doly;

(2) at the bottom of positioning pit, determine bearing pole position, take this as the standard and carry out in the vertical plane vertically to reaching 45 to boring;

(3) the interior instrument of strain meter vertical plane oppositely places boring in groups, and its cable exit is connected with the bearing strut fixation by reverse joint;

(4) load onto bearing pole, adjust direction, in boring, insert mortar;

(5) the interior instrument of strain meter horizontal plane installs on the bearing pole in groups, adjusts direction;

(6) fill concrete, successively hand compaction in the positioning pit.

(7) fill concrete slightly exceeds the former aspect that rolls, and grinds not have successively to shake with small vibrating and rolls, and having shakes rolls, do not have to shake and roll.To dig pit method and boring method of the present invention organically combines, and proposes the method for the burying strain gauge set of the complete adaptation roller compacted concrete characteristics of a cover.

Experimental results show that the inventive method is successful, it makes in groups strain meter be used to monitor dam safety by code requirement becomes possibility, in groups in the strain meter each single strain meter bury underground roll before and after deflection minimum, in the normal range of operation of instrument, the some strain amount of unbalance of strain meter does not surpass permissible value in groups.Press code requirement, instrument setting angle deviation should be less than 1 °, and actual effect can be checked by a strain amount of unbalance.The inventive method significantly reduces roller compacted concrete and digs, fills out workload, and the instrument embedding reliability improves, and has just protected workmanship and construction speed effectively.

Drawings attached 2 of the present invention, for bury underground have in the vertical plane four strain meters five to strain meter schematic diagram in groups.As shown in Figure 2, position, instrument place concrete 10 roll qualified after, dig a small-sized positioning pit 11 earlier, determine the position of instrument bearing pole 6, in vertical plane, bore vertically to hole 16,45 to

hole

12,14,

instrument

4,5,8 oppositely places boring in the strain meter vertical plane in groups, its cable exit is fixedlyed connected with bearing pole 6 by reverse joint 13, each single strain meter is fixed on the bearing pole 6, level still is a forward stube cable 7 to strain meter 3, another level, is not drawn among the figure in 3 vertical direction to strain meter.15 for placing the packing ring of boring instrument among the figure.

Embodiment 1, bury underground have in the vertical plane four instruments five to Strain Meter Set, the layer of concrete at instrument position of living in roll qualified after, dig the positioning pit of long * wide * dark=80 * 70 * 30, locate the edge at the end, hole vertically to reaching 45 to boring three holes, the aperture is 6cm, vertically to hole depth 39cm, 45 is to hole depth 35cm, in boring good hole, put into the dark expansive cement mortar of 5cm, three DI-25 type strain meter cables that assemble reverse joint are put into the hole outwardly respectively, insert in the mortar, load onto bearing pole, adjust direction, in the hole, insert mortar to the aperture, distortion exerts an influence to instrument in order to prevent mortar, should be at instrument stage casing embedding one deck 2mm thick rubber or asphaltic felt packing ring, two levels to DI-25 type strain meter dress bearing on, adjust direction, azimuthal error is answered≤1 °, back-filling in layers concrete in the positioning pit is rejected big footpath aggregate, rams successively with the tack of heavy 1～2kg and tamps by quincunx arrangement, fill concrete should exceed the former aspect 10cm that rolls, with small vibrating grind not have shake roll 2 times after, having shakes rolls 10 times, does not have and rolls 2 times.

Embodiment 2, bury underground have in the plane four instruments five to Strain Meter Set, step and example 1 with, difference is in only bores one vertically to the hole in vertical plane, oppositely place boring after vertically the cable exit of to a instrument assembles reverse joint.

Claims

1, a kind of in roller compacted concrete the method for burying strain gauge set, it is characterized in that:

(1) will be in groups strain meter be inverted to lay and bury underground;

(2) adopt the method for embedding dig pit, hole and combine, dig small-sized positioning pit earlier, again in the positioning pit internal drilling, the instrument in the vertical plane is buried underground with boring method, the instrument in the horizontal plane is buried underground with the method for digging pit;

(3) in groups in the strain meter instrument in the vertical plane oppositely insert in the boring, the instrument lead exit is connected with the bearing strut fixation by reverse joint.

2, according to claim 1 in roller compacted concrete the method for burying strain gauge set, it is characterized in that realizing as follows:

(4) load onto bearing pole, adjust direction, in boring, insert mortar;

(6) fill concrete, successively hand compaction in the positioning pit;

(7) fill concrete slightly exceeds the former aspect that rolls, and grinds not have successively to shake with small vibrating and rolls, and having shakes rolls, do not have to shake and roll.