CN103306296B - Cutting slope frame anchor wall construction method based on soil arching effect - Google Patents

Abstract

The invention belongs to the technical field of geotechnical engineering and specifically relates to a cutting slope frame anchor wall construction method based on the soil arching effect. The method includes: firstly excavating slope plain stages and setting pre-reinforcement piles; calculating the length and the sectional area of anchor rods according to Coulomb active earth pressure acting on anchor walls; manufacturing the anchor rods according to the determinate length and the determinate sectional area of the anchor rods and setting anchor wall bodies; finally performing slope green protection construction. The construction method gives full consideration to interaction of structures between the piles, namely the pre-reinforcement piles can form the soil arching effect between the piles. When the frame anchor walls are constructed, the length and the sectional area of the construction anchor rods can be calculated according to the earth pressure, calculation results are accurate, engineering investment can be saved during construction, a target of safety is achieved, and materials can be saved.

Description

Based on the cut slope frame with anchors wall construction method of soil arching effect

Technical field

The invention belongs to Geotechnical Engineering field, be specifically related to a kind of cut slope frame with anchors wall construction method based on soil arching effect.

Background technology

Along with fast development and the variation of slope supporting structure, in engineering practice, emerge a lot of light supporting structure, as soil nail wall etc. between frame with anchors wall, reinforcing pile between pre-reinforcement stake.But at present Problems existing is that theory calculate is slightly poorer than engineering practice, how the soil pressure as acted on retaining structure calculates and how structure design under stake-anchor-soil interaction calculates.During between pre-reinforcement stake, the structure design of frame with anchors wall is constructed, pre-reinforcement stake is arranged on plain stage of slope, play monolithic stability effect, side slope soil pressure in pre-reinforcement stake conveniently Coulomb's earth pressure calculates, because pre-reinforcement stake can form soil arching effect between stake, act on the effect of the soil pressure between stake on frame with anchors due to " soil arching effect ", can with usually design in the coulomb active earth pressure that adopts different.Design if still conveniently calculated and construct, very large waste can be produced.

Summary of the invention

Object of the present invention is exactly the deficiency existed to solve above-mentioned background technology, provides a kind of cut slope frame with anchors wall construction method based on soil arching effect.

The technical solution used in the present invention is: a kind of cut slope frame with anchors wall construction method based on soil arching effect, comprises the following steps:

(1), at side slope surface earth rock placement and excavation is carried out, smooth domatic;

(2), at the most next stage plain stage of slope of Slope body, pre-reinforcement stake is set along length of slope direction uniform intervals;

(3), according to the coulomb earth pressure computation formula acted on body of wall

$E_a=G\frac{\sin (90-\mathrm{\θ}-\mathrm{\φ})}{\sin (\mathrm{\θ}+\mathrm{\φ}+\mathrm{\δ}-\mathrm{\α})}$

Calculate: anchor rod anchored segment length with anchor pole sectional area A _s=K × E _a/ f _y;

(4), anchor pole is made according to the rock-bolt length determined and anchor pole sectional area;

(5), in the boring of Slope surface uniform intervals, the anchor pole made is inserted in the hole that side slope is bored, and to slip casting in the hole being inserted with anchor pole, form anchor pole wall body of wall;

(6), Green Protection layer is laid at anchor pole wall surface of wall.

In above formula: E _afor effect coulomb active earth pressure on the wall; G is the gravity of the sphenoid ABED before soil arch and soil encircle between the plane of fracture; θ is angle of rupture; φ is soil body angle of internal friction; δ is the angle of friction between frame with anchors wall and the soil body; α is the vertical inclination angle of frame with anchors wall; L _afor anchor rod anchored segment length; K is safety factor; D is bolt diameter; f _rbfor the adhesion strength design load of cement mortar and hole wall; f _yfor the tension design strength of reinforcing bar.

Further, in described step (2), pre-reinforcement stake is reinforced concrete rectangular stake, and sectional dimension is 1.75 × 3.0m, and pile spacing is 5-8m.

Further, in described step (5), anchor spacing is 3-5m, downward-sloping, is 15 °-25 ° with the angle of horizontal plane.

Further, arrange at anchor pole wall surface of wall the grid-like framework be made up of concrete before described step (6), the width of framework is 3-5m.

Further, described Green Protection layer is positioned at the grid of framework, and Green Protection layer is linked network spray thick photoresist or three-dimensional ecology bag.

Between cut slope employing pre-reinforcement of the present invention stake during frame with anchors construction, in view of pre-reinforcement stake can be formed " soil arching effect " between stake, therefore soil arching effect is taken into full account, on anchor pole wall, soil pressure is according to coulomb earth pressure computation, the plane of fracture is drawn from toe by calculating angle of rupture, this plane of fracture is crossing with Soil arch between piles, can not produce sliding force owing to encircleing the soil body below because of the existence of soil arch acts on anchor pole wall, sphenoid then between soil arch and the front plane of fracture of arch is the soil pressure acted on frame with anchors, during the construction of frame with anchors wall, earth pressure gauge calculates length and the sectional area of construction anchor pole thus, result of calculation is more accurate, can cost saving during construction.

This constructure scheme has taken into full account the interaction of works between stake and stake, has both reached safe target, can save material again.This constructure scheme improves light supporting structure design accuracy and the construction method of railway cutting, has filled up the theory of computation and the Construction practices of compound retaining structure.

Accompanying drawing explanation

Fig. 1 is Soil arch between piles effect schematic diagram of the present invention.

Fig. 2 is the soil body distribution schematic diagram after frame with anchors wall of the present invention.

Fig. 3 is the power distribution schematic diagram that the present invention acts on frame with anchors wall.

Fig. 4 is that the power that the present invention acts on frame with anchors wall vows triangle schematic diagram.

Fig. 5 is the structural representation of Construction State of the present invention.

Fig. 6 is longitudinal cross-section cutaway view of the present invention.

Detailed description of the invention

Below in conjunction with the drawings and specific embodiments, the present invention is described in further detail, is convenient to be well understood to the present invention, but they do not form restriction to the present invention.

Cut slope pre-reinforcement stake front baffle anchor pole wall construction method based on soil arching effect of the present invention, comprises the following steps:

First plain stage of slope excavation, smooth domatic is carried out, at the most next stage plain stage of slope of Slope body, pre-reinforcement stake 1 is set, the main reinforcement effect of side slope is played in pre-reinforcement stake, pre-reinforcement stake is reinforced concrete rectangular stake, sectional dimension is 1.75 × 3.0m, in Slope body 5 most subordinate, platform is arranged along length of slope direction uniform intervals, and pile spacing is 5-8m.

Then the construction of frame with anchors wall is carried out, first consider before construction " soil arching effect " that formed between stake and stake, as shown in Figure 1, due to soil arch 2 can be formed under soil body load P effect after pre-reinforcement stake 1 between stake and stake, therefore, act on the effect of the soil pressure between stake on frame with anchors due to " soil arching effect ", can with usually design in the coulomb active earth pressure that adopts different.When not considering that between stake, " soil arching effect " acts on, the soil pressure acted on frame with anchors wall is that sphenoid ABC produces, as shown in Figure 2, but in order to material can be saved and calculate accurately, when considering " soil arching effect ", draw the plane of fracture 7 from toe by angle of rupture and meet at E point with Soil arch between piles, then the soil pressure of delta-shaped region CDE is carried on a shoulder pole by pile, the lateral earth pressure that sphenoid ABED before only having soil arch and soil to encircle between the plane of fracture produces acts on frame with anchors wall, and the rock-bolt length of frame with anchors wall and the determination of spacing are needed to be determined by the soil pressure acted on anchor pole wall, therefore the coulomb active earth pressure acted on when calculating consideration soil arching effect on anchor pole wall is needed, first detect anchor pole wall height H before the computation, slope top surface angle of inclination beta, Soil arch between piles height h, the angle α of anchor pole wall and vertical line, angle of friction δ between anchor pole wall and the soil body and soil body internalfrictionangleφ.

Coulomb active earth pressure concrete grammar on anchor pole wall is as follows:

The coulomb active earth pressure acting on the wall back of the body can be tried to achieve from power arrow triangle as shown in Figure 3, Figure 4, and design formulas is: $E_a=G\frac{\sin (90-\mathrm{\θ}-\mathrm{\φ})}{\sin (\mathrm{\θ}+\mathrm{\φ}+\mathrm{\δ}-\mathrm{\α})}$

And G solves as follows, note S is area symbol, and γ is soil body unit weight, has:

$S_{\mathrm{ADF}}=\frac{1}{2}\mathrm{AF}\×\mathrm{DF}=\frac{1}{2}{h}^2\tan \mathrm{\β}$ $S_{\mathrm{ABL}}=\frac{1}{2}\mathrm{AL}\×\mathrm{BF}=\frac{1}{2}{H}^2\tan \mathrm{\α}$

$\begin{array}{c}{S}_{\mathrm{BEFL}}=\frac{1}{2}(\mathrm{EF}+\mathrm{BL})\×\mathrm{FL}=\frac{1}{2}[H-(h+H\tan \mathrm{\α})\cot \mathrm{\θ}+H]\×(h+H\tan \mathrm{\α})\\ G=S_{\mathrm{ABED}}\×\mathrm{\γ}=(S_{\mathrm{ADF}}+S_{\mathrm{BEFL}}-S_{\mathrm{ABL}})\×\mathrm{\γ}\\ =(\frac{1}{2}{h}^2\tan \mathrm{\β}+\frac{1}{2}{H}^2\tan \mathrm{\α}+\mathrm{Hh})\×\mathrm{\γ}-\frac{1}{2}\mathrm{\γ}{(h+H\tan \mathrm{\α})}^2\cot \mathrm{\θ}\\ =P-Q\cot \mathrm{\θ}\end{array}$

Wherein:

$P=(\frac{1}{2}{h}^2\tan \mathrm{\β}+\frac{1}{2}{H}^2\tan \mathrm{\α}+\mathrm{Hh})\×\mathrm{\γ}$ $Q=\frac{1}{2}\mathrm{\γ}{(h+H\tan \mathrm{\α})}^2$

Soil body gravity G is substituted into wall to the counter-force E of soil wedge body _aobtain:

$E=(P-Q\cot \mathrm{\θ})\frac{\sin (90-\mathrm{\θ}-\mathrm{\φ})}{\sin (\mathrm{\θ}+\mathrm{\φ}+\mathrm{\δ}-\mathrm{\α})}$

By above formula both sides to θ differentiate, order try to achieve θ value, substituted into above formula and can try to achieve active earth pressure E _a.

In above-mentioned formula:

E _a---effect coulomb active earth pressure on the wall;

G---the gravity of the sphenoid ABED before soil arch and soil encircle between the plane of fracture;

H---Soil arch between piles height; θ---angle of rupture; Φ---soil body angle of internal friction;

δ---the angle of friction between frame with anchors wall and the soil body; The vertical inclination angle of α---frame with anchors wall;

β---wall top margin slope and horizontal plane angle; H---frame with anchors wall is high;

S _aDF, S _aBL, S _bEFL---the area of triangle ADF, ABL and polygon BEFL.

According to sectional area and the length of coulomb active earth pressure determination anchor pole on the wall that above-mentioned design formulas calculates, thus design framework anchor pole wall is more accurate, cost saving.

The sectional area length of anchor pole is determined by following formula:

A _s＝K×E _a/f _y

A in formula _s---the sectional area (mm of reinforcing bar ²); E _a---anchor pole axial carrying coulomb active earth pressure design load (N); K---load safety factor, can adopt 2.0 ~ 2.2; f _y---the tension design strength (N/mm of reinforcing bar ²).

The length of anchor pole comprises non-anchored segment length and effective anchoring depth, and non-anchored segment length is determined according to the actual range of rib post with the active plane of fracture or slide plane.Effective anchoring section is determined according to following formula, and checks the permission adhesion stress between anchor pole and mortar.

$L_a=\frac{{\mathrm{KE}}_a}{{\mathrm{\πDf}}_{\mathrm{rb}}}$

$L_a=\frac{{\mathrm{KE}}_a}{n{\mathrm{\πd\ξf}}_b}$

L in formula _a---anchor rod anchored segment length (mm); K---safety factor, can adopt 2.0 ~ 2.5; D---bolt diameter (mm); D---single steel bar diameter (mm); N---reinforcing bar radical; f _rb---the adhesion strength design load of cement mortar and hole wall; f _b---the adhesion strength design load between cement mortar and reinforcing bar; ξ---when adopting more than two or two reinforcing bars, interface adhesion strength reduces coefficient, gets 0.60 ~ 0.85.

The spacing of anchor pole generally gets 2.5 ~ 4.0m.

Anchor pole wall single level should not be greater than 10m.

Anchor pole reinforcing bar should select Ribbed Bar or high-strength finish rolling deformed bar, and diameter is preferably 18 ~ 32mm.

The rock-bolt length finally determined according to aforesaid way and sectional area make anchor pole, and hole at Slope body 5 surface uniform interval with air pressure gun, the anchor pole made is inserted in the hole that side slope is bored, in time to slip casting in the hole being inserted with anchor pole, form anchor pole wall body of wall, anchor pole 6 spacing is 3-5m, downward-sloping, is 15 °-25 ° with the angle of horizontal plane.Meanwhile, arrange latticed framework 3 at anchor pole wall surface of wall, the width of framework is 3-5m, lays Green Protection layer 4 in the grid of anchor pole wall surface of wall framework 3, and Green Protection layer is linked network spray thick photoresist or three-dimensional ecology bag, as shown in Figure 5, Figure 6.

The content be not described in detail in this manual belongs to the known prior art of professional and technical personnel in the field.

Claims (5)

1., based on a cut slope frame with anchors wall construction method for soil arching effect, it is characterized in that, comprise the following steps:

(1), at side slope surface earth rock placement and excavation is carried out, smooth domatic;

(2), at the most next stage plain stage of slope of Slope body, pre-reinforcement stake is set along length of slope direction uniform intervals;

(3), according to the coulomb earth pressure computation formula acted on body of wall

$E_a=G\frac{\sin (90-\mathrm{\θ}-\mathrm{\φ})}{\sin (\mathrm{\θ}+\mathrm{\φ}+\mathrm{\δ}-\mathrm{\α})}$

Calculate: anchor rod anchored segment length with anchor pole sectional area A _s=K × E _a/ f _y;

(4), anchor pole is made according to the rock-bolt length determined and anchor pole sectional area;

(5), in the boring of Slope surface uniform intervals, the anchor pole made is inserted in the hole that side slope is bored, and to slip casting in the hole being inserted with anchor pole, form anchor pole wall body of wall;

(6), Green Protection layer is laid at anchor pole wall surface of wall;

In above formula: E _afor effect coulomb active earth pressure on the wall; G is the gravity of the sphenoid ABED before soil arch and soil encircle between the plane of fracture; θ is angle of rupture; φ is soil body angle of internal friction; δ is the angle of friction between frame with anchors wall and the soil body; α is the vertical inclination angle of frame with anchors wall; L _afor anchor rod anchored segment length; K is safety factor; D is bolt diameter; f _rbfor the adhesion strength design load of cement mortar and hole wall; f _yfor the tension design strength of reinforcing bar.

2. the cut slope frame with anchors wall construction method based on soil arching effect according to claim 1, is characterized in that: in described step (2), pre-reinforcement stake is reinforced concrete rectangular stake, and sectional dimension is 1.75 × 3.0m, and pile spacing is 5-8m.

3. the cut slope frame with anchors wall construction method based on soil arching effect according to claim 1, is characterized in that: in described step (5), anchor spacing is 3-5m, downward-sloping, is 15 °-25 ° with the angle of horizontal plane.

4. the cut slope frame with anchors wall construction method based on soil arching effect according to claim 1, it is characterized in that: arrange at anchor pole wall surface of wall the grid-like framework be made up of concrete before described step (6), the width of framework is 3-5m.

5. the cut slope frame with anchors wall construction method based on soil arching effect according to claim 4, is characterized in that: described Green Protection layer is positioned at the grid of framework, and Green Protection layer is linked network spray thick photoresist or three-dimensional ecology bag.