CN101691759A - Construction method for digging composite environmental protection base of anchorage bar adding rock - Google Patents
Construction method for digging composite environmental protection base of anchorage bar adding rock Download PDFInfo
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- CN101691759A CN101691759A CN200910067507A CN200910067507A CN101691759A CN 101691759 A CN101691759 A CN 101691759A CN 200910067507 A CN200910067507 A CN 200910067507A CN 200910067507 A CN200910067507 A CN 200910067507A CN 101691759 A CN101691759 A CN 101691759A
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- digging
- dowel
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Abstract
The invention discloses a construction method for digging a composite environmental protection base of an anchorage bar adding rock, comprising the following steps: firstly, adopting a construction machinery to drill holes on the ground, putting anchorages into holes after designed depth is achieved; grouting gaps around the anchorages; when slurry is solidified and cured to reach 30% of designed strength, artificially digging foundation pit earth body and achieving designed depth; after the foundation pit is shaped, shaving off cured slurry around the anchorages of the parts above the pit bottom; putting a basic main post reinforcement cage composed of a main reinforcement and a stirrup, binding or welding anchorages and the basic main post reinforcement cage into a whole; buckling the screw thread part of the upper part of anchorages with a nut and a spacer; and casting concrete in the foundation pit and simultaneously embedding a foundation bolt. By analytical calculation and experimental verification, the construction method well resists exterior load, and meets the requirement of environmental protection of engineering construction, thereby saving the usage of material, reducing the volume of stone and earthwork, and reducing influence on the environment.
Description
Technical field
The present invention relates to the basic field of high pressure, super-pressure and extra-high voltage power line tower.
Background technology
State Grid Corporation of China to power engineering construction related environmental protection pay much attention to, environmental protection work is brought up to the height of national grid sustainable development.Requirement among the DL/T5219-2005 " aerial power transmission line basic engineering technical stipulation "; basic engineering must adhere to protecting environment and the principle that economizes on resources; according to circuit landform, execution conditions, geotechnical investigation data; take all factors into consideration basic pattern and design scheme, make basic engineering reach the purpose of safety, economical rationality.
Pole and tower foundation is as the important component part of overhead transmission line, and its cost, duration and labor consumption account for very big proportion in whole line project.Add up according to interrelated data: in general overhead transmission line engineering construction, the basis duration accounts for half of whole duration of a project, the basis freight volume accounts for 60%, and expense accounts for 15%～35% of body cost, and the shared ratio of foundation cost expense also can be higher under the special foundation condition.This shows,, reduce engineering construction cost, select for use science and rational basic pattern and construction technology imperative with suiting measures to local conditions for concrete and the amount of reinforcement that reduces the project of transmitting and converting electricity pole and tower foundation.
The basis accomplished not only economy but also environmental protection in power transmission sequence in the past, no more than adopting undisturbed soil basis pattern, Here it is draws and digs type basis or Rock Bolt Foundation.Digging foundation is direct digging foundation hole in ground, inserts reinforcing bar, penetration concrete and the basis that forms.This basis earthwork is less, and is less to landform and vegetation deterioration, can make full use of the undisturbed soil characteristic, pull out bearing capacity on it to improve, and can reduce the lateral deformation on basis, do not need formwork when casting concrete again, but the reduction of erection time is reduced operating expenses, and what it calculated employing is shearing method.
Rock Bolt Foundation is a kind of base for post of directly building on the rock, is directly to hole, insert reinforcing bar on rock, pours into cementitious materialss such as pea gravel concreten or mortar then, the basis that reinforcing bar and rock tight bond are formed.Though this basic calculation is complicated, calculating train of thought is more clearly.Because this basis utilizes rock itself, have advantages such as the concrete of saving, steel and site operation workload are little, remarkable economic efficiency is arranged.
In a word, digging foundation or Rock Bolt Foundation are paid attention to by vast work about electric power person once coming out as a kind of basic pattern.On the one hand, they have made full use of the high-bearing of undisturbed soil or rock, the characteristics of low distortion, bear big vertical force of shaft tower and horizontal force; On the other hand, its excavated volume is little, has reduced environment damage, has reduced base concrete and steel material again.Certainly, for digging foundation himself shortcoming is arranged also, it is higher to the geology conditional request, and general requirements geology is viscosity class soil, draws to dig for broken rock and soil and foundation ditch to be difficult to moulding and maybe can not to draw the tower position of digging and can not use.Because it is limited that the expansion of digging foundation bottom is dug, the base plate diameter should not be too big, uses in the tower position that basic role power is bigger, and then restriction is used.For Rock Bolt Foundation himself shortcoming is arranged also, this basic general requirements rock is exposed, or covering layer and weathered layer are more shallow, but this tower position is difficult to just in time appear on the tower position of circuit.If the rock stratum is very dark, just be difficult to use, often be designed to heavy excavation type basis this moment, and earth volume is very big, influences environment, does not make full use of the bearing capacity of basement rock again.
Investigation shows that a lot of regional geology conditions mainly are that the face of land is covered by argillic horizon, and thickness is generally 1.5～2.5m, below is severely-weathered or the medium weathering rock stratum.As adopting the heavy excavation pattern, easily cause environment extensive damage and the big consequence of Foundation Design consumable quantity on this regional electric power line pole tower basis; If employing digging foundation, thickness of clay soil are often not enough, can't all manually draw and dig; If employing rock foundation needs also to cause excavated volume to increase top layer clay excavation, be unfavorable for environmental protection.
Summary of the invention
Technical problem to be solved by this invention provides a kind of job practices of digging composite environmental protection base of anchorage bar adding rock; the basis of Jian Zaoing has made full use of undisturbed soil ground bearing capacity height, the little good engineering mechanics performance of distortion by this method; satisfy the environmental protection requirement of engineering construction, the economical with materials amount.
For solving the problems of the technologies described above, the invention provides a kind of job practices of digging composite environmental protection base of anchorage bar adding rock, it is characterized in that comprising the following steps:
(1) adopts earlier construction machinery to hole on the ground, put into dowel after reaching projected depth;
(2) be in the milk in the space around the dowel;
(3) when the slurry setting and hardening reach design strength 30% after begin manually to draw and dig the foundation pit earth tire, and reach projected depth;
(4) after the foundation ditch moulding, cut and pull out the slurry of the end, hole with sclerosis around the dowel on top;
(5) put into the basic principal post reinforcing cage that constitutes by main muscle and stirrup, with dowel and the colligation of basic principal post reinforcing cage or be welded into integral body;
(6) screw thread of dowel upper end is partly buckled well nut and pad;
(7) fluid concrete is imbedded stone bolt simultaneously in foundation ditch.
In order to increase anchorage effect, at the two-sided welding short steel rod in dowel lower end.
Pole and tower foundation always is embedded in different soil conditions and the different geological environments, ground and basic interphase interaction, common carrying.The foundation bearing capacity characteristic not only depends on the basis, also depends on basic ambient medium (soil body).Because the effect of tension and compression alternation external force is born on shaft tower and basis for a long time, and resistance to plucking and the stable controlled condition that normally designs of overturning or slip resistance analysis.In excavation backfill type basis, if backfill intensity can not get assurance, then can not form consolidation between backfill and hole wall, can not form the resistance to plucking reverse taper when being subjected to the pulling force load action, and distortion is big, anti-pulling capacity reduces.Therefore, making full use of undisturbed soil ground bearing capacity height, the little good engineering mechanics performance of distortion, is the basic principle that we determine basic pattern.Drawing and digging the compound basis of adding rock anchor pole is exactly to make full use of the undisturbed soil mechanical property, gives full play to this basic pattern advantage.
The present invention calculates and verification experimental verification by analysis; but digging foundation part and the collaborative work of anchor pole part under ultimate bearing capacity; resist external load well; can make full use of undisturbed soil ground bearing capacity height, the little good engineering mechanics performance of distortion; satisfy the environmental protection requirement of engineering construction, the economical with materials amount is by comparing with general digging foundation to this basis; tangent tower generally can be saved concrete about 25%, and basic steel can be saved about 20%.Angle tower generally can be saved concrete about 30%, and basic steel can be saved about 23%.Owing to select anchor pole to dig the compound basis of matching with drawing, can also further reduce embedded depth of foundation, thereby reduce earthwork, minimizing is to the influence of environment.
The test example
Re-set target according to aspects such as the construction of experimental study, designing and calculating, same place draws and digs+anchor pole combined type basis, digging foundation, anchor pole basis, the counterpart consistent size in digging foundation and the combined type basis wherein, the anchoring body degree of depth on anchor pole basis, size, radical etc. are consistent with the combined type basis.Two places are chosen in this test, and the buried depth of digging foundation is respectively 2.3m and 2.8m, and anchor rod anchored body length is respectively 3.3m and 3.0m.
Result of the test
According to ground and basic performance state in trial load～displacement curve relation and the loading procedure, and extreme displacement equivalent-load power determines method, and the bearing capacity of experimental basis sees Table 1, and corresponding displacement situation sees Table 2.
The ultimate bearing capacity value of table 1 experimental basis
The displacement of table 2 experimental basis ultimate limit state correspondence
Description of drawings
The basic elevation that Fig. 1 builds for job practices of the present invention;
Fig. 2 is the sectional drawing along 1-1 line among Fig. 1;
Fig. 3 is the sectional drawing along 2-2 line among Fig. 1;
Fig. 4 is the dowel schematic diagram.
The specific embodiment
With reference to Fig. 1, Fig. 2, Fig. 3, Fig. 4, the present invention includes the following step:
(1) adopts earlier machinery to hole 9 on the ground, put into dowel 3, the two-sided welding short steel rod 8 in dowel lower end after reaching projected depth;
(2) be in the milk in the space around the dowel and form anchor pole 10, but pressure grouting in case of necessity, and the material of grouting is that strength grade is C25 pea gravel concreten or M15 mortar;
(3) when the concrete mortar setting and hardening reach design strength 30% after begin manually to draw and dig the foundation pit earth tire, and reach projected depth;
(4) after the foundation ditch moulding, cut and pull out the concrete of the end, hole with sclerosis around the dowel of top;
(5) put into the basic principal post reinforcing cage that constitutes by main muscle 5 and stirrup 6, with dowel and the colligation of basic principal post reinforcing cage or be welded into integral body;
(6) screw thread of dowel upper end is partly buckled well nut and pad 7;
(7) cast C20 concrete forms basic principal post 1 and stone bolt 4 is imbedded on basic chassis 2 simultaneously in foundation ditch.
Chassis, basis and basic principal post adopt digging foundation to calculate principle and promptly adopt shearing method, and the bottom adopts rock bolt to calculate principle.Digging foundation part and anchor pole part are resisted the active force that the top iron tower transmits together, wherein the cohesion between the relative shearing of the soil body and anchor pole and the rock is born jointly on the surface of shear that formed in the soil body by digging foundation of uplift force and horizontal force, and downforce and horizontal force are born by the rock face under the basic chassis.
One, draw dig+anchor pole combined type foundation bearing capacity calculates
Draw dig+anchor pole combined type basis Ultimate Up-lift Bearing Capacity theoretical calculation formula is as follows:
T
u＝k
DT
1+k
AT
2
T
UThe ultimate bearing capacity on-combined type basis;
T
1The ultimate bearing capacity of-full digging foundation;
T
2The ultimate bearing capacity of-Rock Bolt Foundation;
k
DThe performance degree of-digging foundation, k
D≤ 1;
k
AThe performance degree of-rock foundation, k
A≤ 1.
According to the test result analysis of table 1 and table 2, k
DAnd k
AValue is 1, promptly draw to dig+when the carrying of anchor pole combined type basis reached ultimate limit state, its composition was drawn to dig with the anchor pole bearing capacity and is all given full play to.The anti-pulling capacity that digs with the anchor pole assembly of drawing on combined type basis is calculated as follows:
1, draws the bearing capacity calculation of digging assembly
(1) draws and dig the part bearing capacity and can calculate according to " aerial power transmission line basic engineering technical stipulation " (DL/T 5219-2005) related content and regulation.
(2), draw the ultimate bearing capacity that digs assembly and can calculate by following formula (1) according to achievement in research:
T
1=A
1 (theoretical value)CH
2+ A
2 (theoretical values)γ H
3+ Q
f(1)
Wherein, Q
fBe the basis deadweight;
γ is a soil body severe;
H is an embedded depth of foundation;
A
1And A
2Be the Dimensionless Calculation constant relevant with embedded depth of foundation with baseplate width ratio (H/D) with internalfrictionangle,
2, anchor pole assembly bearing capacity calculation
According to result of the test, with draw dig+corresponding anchor pole basis, anchor pole combined type basis is when load-bearing destroys, surface displacement is significant change not, therefore, can think not spot basement rock body general shear failure, so at calculating anchor pole assembly bearing capacity T
2The time corresponding collapse state be respectively that dowel is broken, dowel is extracted and anchoring body is extracted, its computational methods and parameter value according to " aerial power transmission line basic engineering technical stipulation " (DL/T5219-2005) with the regulation of other related data.
Two, draw and dig+optimization of anchor pole combined type basic engineering
1. anti-pulling capacity calculation optimization
Bearing capacity calculation is a theoretical value in the formula (1), has enough security reliabilities for guaranteeing design, based on Probability Statistics Theory, guarantees that bearing capacity has 95% confidence level, draw with the A place to dig+anchor pole combined type basic test data are sample, to calculated value T
URevise, calculate correction factor γ
TFor: γ
T=0.83, promptly get and calculate bearing capacity and need satisfy following formula (2):
γ
f·T
E≤γ
T·T
U＝0.83(k
DT
1+k
AT
2) (2)
2. anchor member optimized dimensions
The existing anchor pole pull-out test data of other industry shows: in the weathered rock formation, the bonding ultimate bearing capacity differs greatly between anchor hole wall and anchor concrete or mortar, mainly is the influence that its adhesion strength is subjected to many conditions and geologic(al) factor (as the character of rock stratum, buried depth, underground water, different method for filling etc.).The anchor rod experiment that carries out shows: in the weathered rock formation, the anchor pole bearing capacity depends primarily on the section at 0～3m, but considers that from the security reliability angle the effective anchorage length of single anchor pole should be got 4～6m in the combined type basis.
Claims (2)
1. the job practices of a digging composite environmental protection base of anchorage bar adding rock is characterized in that comprising the following steps:
(1) adopts earlier construction machinery to hole on the ground, put into dowel after reaching projected depth;
(2) be in the milk in the space around the dowel;
(3) when the slurry setting and hardening reach design strength 30% after begin manually to draw and dig the foundation pit earth tire, and reach projected depth;
(4) after the foundation ditch moulding, cut and pull out the slurry of the end, hole with sclerosis around the dowel on top;
(5) put into the basic principal post reinforcing cage that constitutes by main muscle and stirrup, with dowel and the colligation of basic principal post reinforcing cage or be welded into integral body;
(6) screw thread of dowel upper end is partly buckled well nut and pad;
(7) fluid concrete is imbedded stone bolt simultaneously in foundation ditch.
2. the job practices of digging composite environmental protection base of anchorage bar adding rock according to claim 1 is characterized in that also being included in the two-sided welding short steel rod in dowel lower end, to increase anchorage effect.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN200910067507A CN101691759A (en) | 2009-09-04 | 2009-09-04 | Construction method for digging composite environmental protection base of anchorage bar adding rock |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN200910067507A CN101691759A (en) | 2009-09-04 | 2009-09-04 | Construction method for digging composite environmental protection base of anchorage bar adding rock |
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| Publication Number | Publication Date |
|---|---|
| CN101691759A true CN101691759A (en) | 2010-04-07 |
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ID=42080469
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|---|---|---|---|
| CN200910067507A Pending CN101691759A (en) | 2009-09-04 | 2009-09-04 | Construction method for digging composite environmental protection base of anchorage bar adding rock |
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Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107964977A (en) * | 2017-11-30 | 2018-04-27 | 中国电力科学研究院有限公司 | The composite foundation and its construction method of a kind of karst landform |
| CN110805060A (en) * | 2019-11-13 | 2020-02-18 | 山东建筑大学 | Base structure for stay wire of stay wire tower and stay wire fixing method |
| CN111576469A (en) * | 2020-04-02 | 2020-08-25 | 国网浙江省电力有限公司湖州供电公司 | Novel power transmission line tower foundation and construction method |
| CN111910671A (en) * | 2020-07-20 | 2020-11-10 | 国网浙江省电力有限公司丽水供电公司 | Prestressed anchor rod combined excavation composite foundation and construction method thereof |
| CN112195960A (en) * | 2020-09-27 | 2021-01-08 | 华侨大学 | Method for determining partition length of ground bolt |
| CN113431075A (en) * | 2021-07-27 | 2021-09-24 | 中国电建集团福建省电力勘测设计院有限公司 | Herringbone pile anchor assembly type foundation suitable for low-voltage power transmission line |
-
2009
- 2009-09-04 CN CN200910067507A patent/CN101691759A/en active Pending
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107964977A (en) * | 2017-11-30 | 2018-04-27 | 中国电力科学研究院有限公司 | The composite foundation and its construction method of a kind of karst landform |
| CN110805060A (en) * | 2019-11-13 | 2020-02-18 | 山东建筑大学 | Base structure for stay wire of stay wire tower and stay wire fixing method |
| CN110805060B (en) * | 2019-11-13 | 2022-02-08 | 山东建筑大学 | Base structure for stay wire of stay wire tower and stay wire fixing method |
| CN111576469A (en) * | 2020-04-02 | 2020-08-25 | 国网浙江省电力有限公司湖州供电公司 | Novel power transmission line tower foundation and construction method |
| CN111910671A (en) * | 2020-07-20 | 2020-11-10 | 国网浙江省电力有限公司丽水供电公司 | Prestressed anchor rod combined excavation composite foundation and construction method thereof |
| CN112195960A (en) * | 2020-09-27 | 2021-01-08 | 华侨大学 | Method for determining partition length of ground bolt |
| CN113431075A (en) * | 2021-07-27 | 2021-09-24 | 中国电建集团福建省电力勘测设计院有限公司 | Herringbone pile anchor assembly type foundation suitable for low-voltage power transmission line |
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Open date: 20100407 |