A kind of geotechnical grid retaining wall and construction method thereof
Technical field
The present invention relates to the retaining wall technical field for side slope protection and reinforcing, particularly a kind of variable cross-section geotechnical grid retaining wall and construction method thereof.
Background technology
In recent years, along with the extensive development of China's speedway and airport construction, high-filled embankment, it is usually visible that the Gravity Retaining Walls such as boundary are enclosed on high cutting slope and embankment airport, the stability and security of these Gravity Retaining Walls is one of ubiquitous key issues in highway or airport construction, the quality of this Resolving probiems, not only affect the construction period of whole engineering, construction quality, construction costs, and the safety in operation process and social benefit are all had a great impact, therefore the research strengthening side slope guard technology improves highway, an important ring of airport construction phase and period of service benefit.
Retaining wall is widely used in highway and airport construction as a kind of conventional slope protection measures.Due to some regional building stones abundance of China, gather materials on the spot conveniently, add construction method simply, therefore, in the past in a very long time, the gravity retaining wall of barnacle is the main retaining structure extensively adopted in China's civil engineering.Gravity Retaining Wall relies on the deadweight of wall body to keep stable, but due to Gravity Retaining Wall cross dimensions large, wall body is heavier, higher to ground requirement for bearing capacity; The quantity of bricklaying is simultaneously many, and labour intensity is high, and construction speed is slow, and lack area application inconvenience at landform difficulty, building stones, its shortcoming used is obvious; Particularly bricklaying metope cannot be afforested, and when it is used as embankment, cutting slope support structure and curb wall, not only affects beautifying of Roadside Landscape, and does not meet the requirement of environmental protection.But along with society and expanding economy; day by day be subject to people to environment and ecological protection to pay attention to; highway not only needs the function bearing rapid transit passage; also the requirement being endowed protecting ecology, beautifying the environment simultaneously, therefore takes into full account in highway construction that the environmental harmony of greening vegetation along the line, highway structure and natural landscape along the line is just becoming common recognition and an urgent demand of the whole society.
In subgrade support protection structure, except Gravity Retaining Wall, reinforced earth bulkhead, Prestressed Anchor Cable Poling Board Wall, anchor ingot plate barricade etc. in addition conventional in current highway engineering, the application of said structure in engineering practice achieves a large amount of engineering experience, but also there is the problems such as construction is complicated, self gravitation is comparatively large, environmental disruption is comparatively serious, shock-damping energy-dissipating effect is not obvious.With regard to cutting slope defending, adopt mortar flag stone, slabstone or the bricklaying such as concrete skeleton and sprayed mortar safeguard procedures more, although above-mentioned safeguard procedures can reach side slope protection object, but it is large to there is engineering quantity, labour intensity is high, ecological environment be difficult to recover and with the defect such as environmental landscape is inharmonious.And the protection to fills embankment side slope, except bricklaying pattern, most employing plane geosynthetics (as geo-grid, geotechnological gauze pad, three-dimensional earthwork etc.) is in conjunction with the method for grass planting, although above-mentioned safeguard procedures achieve certain effect in engineering practice, but also come with some shortcomings, be mainly manifested in planar materials and domatic frictional resistance is little, the overcoat formed is thin, erosion resistance is low, under the effect of concentrated flow, easily produce surface and come off, cause slope erosion to be out of shape, and then slip and collapse, the subgrade defect such as cave in.
Perfect gradually along with national expressway network, substantially carries out in mountain area at the speedway built and plan to build at present, will certainly occur a large amount of slope support engineerings.Many speedway route major parts are in Freeway of Mountain Range, inevitably make route pass through with cutting or embankment form in a lot of section, have occurred a large amount of slope project; Meanwhile, cutting excavation and filling of high embankment must have an impact to ecological environment along the line.How to accomplish while highway construction, stability of slope should be ensured, make construction smooth, guarantee highway construction quality, effectively recover along the line ecological again, reduce the destruction to natural ecological environment as far as possible, preventive works and surrounding environment and natural landscape are coordinated, the theory realizing built environment friendly speedway is one of key technical problem of facing of this speedway.
On the other hand; along with country's continuing to increase existing cultivated land protection dynamics; reduce an important guiding principle of taking up an area and having become expressway construction; this just requires when Freeway of Mountain Range building highway; when meeting route alignment requirement; except adopting the form of light fill and low cutting as far as possible; subgrade support protection structure can be used in a large number; put the ratio of slope of gradient slope; reduce subgrade cross section thickness; to reach the object reducing occupation of land, particularly all the more so at the linear restricted Special zone in mountain area.
Above 2 points; force engineers and technicians must while highway construction; namely stability of slope will be ensured; make construction smooth; guarantee highway construction quality; effectively recover along the line ecological again; reduce the destruction to natural ecological environment as far as possible; preventive works and surrounding environment and natural landscape are coordinated; that is in the Slope Design of following mountain area, must propose or preferentially select some from heavy and light, low to ground requirement for bearing capacity, avoid opening greatly and dig greatly, available protecting environment, realize the light flexible support engineering structure of ecological recovery.
Chinese utility model patent ZL03219002.6 proposes a kind of geotechnical grid vegetation barricade, and this utility model is banketed in the geotechnical grid opened, and layer-by-layer rolling fills, and forms reinforced retaining wall.This utility model belongs to point supporting system, has the feature of concrete or stone-laying barricade and reinforced earth bulkhead concurrently, can coordinate the stressed of body of wall and distortion preferably, and meanwhile, effectively can disperse base stress, sedimentation is less.The geotechnical grid vegetation wall-retaining structure adopted, has the advantages such as lightweight, specification standards, easy construction, ensureing, under stable prerequisite, can plant flowers and plants in geotechnical grid, reaching greening domatic, beautifying the environment.But because geotechnical grid material construction is higher, therefore whole construction costs is higher, and engineering practice and theoretical study results show, the horizontal movement of barricade middle and lower part is comparatively large, has considerable influence to the safety of barricade.
Chinese invention patent ZL201010213540.X proposes a kind of flexible retaining wall with rigid support, this invention is provided with the gravel drainage blanket of the rigid bracing beam connected with side slope in 1/2 place's making one deck of wall height, the effect increasing barricade strength and stiffness is played by rigid support, thus enhance the resistance to overturning of barricade, improve the safety factor of barricade, but the cross section type of barricade is uniform section, do not take into full account the stress characteristic of barricade, and do not give full play to the material property of geotechnical grid, cause the waste of material, long construction period, construction costs is higher.
Summary of the invention
For solving above technical problem, the invention provides a kind of geotechnical grid retaining wall adopting variable cross-section form, be light flexible support engineering structure, not only can save construction costs, the horizontal movement of retaining wall can also be effectively reduced, thus ensure the safety factor of retaining wall.
For solving the problems of the technologies described above, present invention employs a kind of geotechnical grid retaining wall, basal layer is equipped with rigid layer, rigid layer is laid bottom gravel drainage blanket, bottom gravel drainage blanket upwards lays fill stratum successively, in described fill stratum, is equipped with at least one layer of gravel drainage blanket; From rigid layer, often increase one deck geotechnical grid receding form certain slope, until retaining wall top, every one deck geotechnical grid is connected with Bar Anchorage with neighbouring geotechnical grid, and described retaining wall is set to variable section structure, more upwards sectional area is less, and retaining wall thickness is less; Described retaining wall is divided into the first half and the latter half, and described the first half and the latter half respectively account for 1/2 of whole retaining wall height, and the thickness of described the first half is 1/2 ~ 3/4 of the latter half thickness; Described retaining wall is provided with elongated bar strip, described elongated bar strip thickness is 1/2 ~ 1 of whole retaining wall height, described the first half is also provided with at least one bar strip, and described bar strip thickness and the ratio of elongated bar strip thickness equal the ratio of retaining wall the first half thickness and the latter half thickness.
Described elongated bar strip is arranged on retaining wall height 1/3 place.
Described bar strip is separately positioned on 1/2,3/4 and 7/8 place of whole retaining wall height.
The variable cross-section intersection of described retaining wall is provided with narrow bar strip, and described narrow bar strip thickness is identical with the thickness of the fill stratum of adjacent less thickness, and the height of aspect ratio fill stratum exceeds 1/4.
The described gradient is less than 1:0.25.
Up lay one deck gravel drainage blanket every 2m at bottom gravel drainage blanket, it is different from bottom gravel drainage blanket that gravel drainage blanket removes thickness, and all the other structures are identical with bottom gravel drainage blanket.
Described basal layer is stirred by cement and sand gravel and forms, wherein the content of cement is 20%, the content of sand gravel is 80%, the diameter of sand is 0.5 ~ 2mm, and the diameter of gravel is 2 ~ 50mm, uses length 1.5m, strengthening nail based on the reinforcing bar of diameter 12mm, arrange one along basal layer length direction every 2m, arrange one along retaining wall thickness direction every 1m, squeeze into basal layer; Described geotechnical grid is of a size of height 20cm, welding torch 80cm, and fill out cement-sandy gravel in geotechnical grid and form rigid layer, it is identical that its cement-sandy gravel and basal layer use; Rigid layer lays geotechnical grid, and in geotechnical grid, back-up sand gravel forms described bottom gravel drainage blanket; Also compacting of banketing in geotechnical grid forms described fill stratum, and fill stratum planeness is less than 2.0cm, and filler requires even particle size, and maximum particle diameter must not be greater than 10cm.
Retaining wall top adopts sixteen dirt to fill, and its cross section is U-shaped groove structure.
Compared with the retaining structure that the present invention is traditional with traditional mortar flag stone retaining wall, reinforced earth bulkhead, Prestressed Anchor Cable Poling Board Wall, anchor ingot plate barricade etc., the variable cross-section geotechnical grid retaining wall that the present invention proposes has following advantage: structure is light, lower to the requirement of bearing capacity of foundation soil; Cancel bricklaying, afforesting wall surfaces, ecological, environmental protective, beautify view.Compared with similar geotechnical grid barricade, the variable cross-section geotechnical grid retaining wall that the present invention proposes has following advantage: the horizontal movement reducing retaining wall, improves its safety factor; Save geotechnical grid and reinforcing bar, save labour, and shorten the duration, remarkable in economical benefits.The present invention can be widely used in the place that speedway, airport etc. need to use gravity retaining wall.
Present invention also offers a kind of construction method of geotechnical grid retaining wall, comprise the following steps as follows:
One, according to design drawing, carry out unwrapping wire, excavation, mechanical equivalent of light excavation stops excavation to apart from during substrate design absolute altitude 20 ~ 30cm, with labor cleaning to design altitude, rolls with vibrating roller; Its standard performs with reference to the relevant provision in " Highway Roadbed Construction Technology specification "; On-the-spot test is carried out to bearing capacity of foundation soil, the requirement of bearing capacity of foundation soil should be met;
Two, making basal layer; Basal layer is stirred by cement and sand gravel and forms, wherein the content of cement is 20%, the content of sand gravel is 80%, the diameter of sand is 0.5 ~ 2mm, and the diameter of gravel is 2 ~ 50mm, uses length 1.5m, strengthening nail based on the reinforcing bar of diameter 12mm, arrange one along foundation length direction every 2m, retaining wall thickness direction arranges one every 1m, squeezes into basis and plays reinforcement effect;
Three, making rigid layer; After basal layer has been constructed, basal layer opens geotechnical grid, be 50cm by length, diameter is that the reinforcing bar of 12mm prolongs retaining wall length direction and arranges one every 2m, one is arranged every 1m along retaining wall thickness direction, opened by geotechnical grid fixing with reinforcing bar, inside fill out cement-sandy gravel, cement-sandy gravel is identical with basal layer;
Four, gravel drainage blanket bottom making; Rigid layer opens geotechnical grid, interior back-up sand gravel, as wall body drainage blanket;
Five, making fill stratum; Bottom gravel drainage blanket lays geotechnical grid, bankets with loader, loader by importer to fall soil, be aided with artificial leveling simultaneously; Walk in the lattice room that loader bankets after leveling, banket complete to this layer forward successively, forbid loader to roll, destroy geotechnical grid; Carry out degree of compaction and planeness detection in time, degree of compaction is greater than design load, and planeness is less than 2.0cm.Geotechnical grid filler requires even particle size, and maximum particle diameter must not be greater than 10cm; The position small vibrating that distance panel is comparatively near, large roller is not easily close rams compacting.Making second layer fill stratum on the bottom first layer fill stratum that making is complete, making third layer fill stratum on second layer fill stratum is until retaining wall top, every upwards increase one deck geotechnical grid receding certain distance, form the gradient being less than 1:0.25, after every layer of geotechnical grid opens and bankets, all adopt length 50cm, the Bar Anchorage of diameter 12mm connects, in order to strengthen the globality of retaining wall.When making is to retaining wall height 1/2 place, upwards the retaining wall thickness of making is the half of retaining wall the latter half thickness;
Six, making gravel drainage blanket; To bottom gravel drainage blanket upwards every 2m making one deck gravel drainage blanket;
Seven, the elongated bar strip of making; The fill stratum at retaining wall height 1/3 place lays geotechnical grid, inside fills out cement-sandy gravel, the thickness of elongated bar strip is 1/2 ~ 1 of whole retaining wall height;
Eight, making bar strip and narrow bar strip; At 1/2,3/4,7/8 place of retaining wall height making bar strip respectively, filling concrete sand gravel in the geotechnical grid of bar strip, the thickness of bar strip is the half of retaining wall height.The narrow bar strip of making on the bar strip at 1/2 place of retaining wall height, filling concrete sand gravel in the geotechnical grid of narrow bar strip, its geotechnical grid adopts the height of 25cm;
Nine, making retaining wall top; Retaining wall top adopts sixteen dirt to fill, and makes U-shaped plough groove type cross section.
The method can be guaranteed both quality and quantity and be completed the construction of retaining wall efficiently.
Accompanying drawing explanation
Fig. 1 is structural representation of the present invention;
Fig. 2 is the partial schematic diagram at retaining wall variable cross-section place of the present invention;
Fig. 3 (a ~ d) shows the impact of depth-width ratio for flexible retaining wall horizontal distortion feature;
Fig. 4 (a ~ d) shows the impact of the gradient for flexible retaining wall horizontal distortion feature;
The preloading of Fig. 5 (a ~ b) display surface is for the impact of flexible retaining wall horizontal distortion feature;
The retaining wall structure schematic diagram that Fig. 6 (a ~ e) is bar strip diverse location, the retaining wall structure for wall back of the body bar strip diverse location has carried out finite element analysis computation, have employed the computation model of the retaining wall of different bar strip position; Wherein:
Fig. 6 (a) is bottom reinforcement;
Fig. 6 (b) is H/3 place reinforcement (H represents retaining wall height, and H/3 represents 1/3 of retaining wall height, lower same);
Fig. 6 (c) is H/2 place reinforcement;
Fig. 6 (d) is H/2 place reinforcement;
Fig. 6 (e) is H place reinforcement;
The safety factor of retaining wall when Fig. 7 is bar strip diverse location;
The computation model that Fig. 8 (a ~ h) is the different reinforcement number of plies, shows the impact for the safety factor of retaining wall of the position of reinforced bands and spacing; Wherein:
Fig. 8 (a) is without reinforcement;
Fig. 8 (b) is middle part one deck reinforcement;
Fig. 8 (c) is the two-layer reinforcement in middle and upper part (being respectively H/2 and 3H/4 bottom bar strip distance retaining wall);
Fig. 8 (d) is three layers, middle and upper part reinforcement (being respectively H/2,3H/4 and H bottom bar strip distance retaining wall);
Fig. 8 (e) is the two-layer reinforcement in middle and lower part (being respectively H/3 and H/2 bottom bar strip distance retaining wall);
Fig. 8 (f) is three layers, middle and lower part reinforcement (be respectively 0 bottom bar strip distance retaining wall, H/3 and H/2);
Fig. 8 (g) is three layers, middle and lower part reinforcement (being respectively 2H/25, H/3 and H/2 bottom bar strip distance retaining wall);
Fig. 8 (h) is three layers, middle and lower part reinforcement (being respectively H/5, H/3 and H/2 bottom bar strip distance retaining wall);
Fig. 9 shows the impact of the different reinforcement number of plies for safety factor;
Computation model schematic diagram in the geotechnological lattice retaining wall structure that Figure 10 (a ~ c) is variable cross-section provided by the present invention during bar strip diverse location; Wherein:
Height bottom the positional distance retaining wall that Figure 10 (a) is bar strip is H/3, H/2,3H/4 and 7H/8 respectively;
Height bottom the positional distance retaining wall that Figure 10 (b) is bar strip is H/3, H/2,2H/3 and 7H/8 respectively;
Height bottom the positional distance retaining wall that Figure 10 (c) is bar strip is H/3, H/2,2H/3 and 3H/4 respectively;
Figure 11 shows bar strip thickness (distance that horizontal direction extends inside the retaining wall) impact on safety factor.
In figure: 1, basal layer, 2, rigid layer, 3, bottom gravel drainage blanket, 4, fill stratum, 5, gravel drainage blanket, 6, elongated bar strip, 7, bar strip, 8 narrow bar strips, 9, retaining wall top.
Detailed description of the invention
Below in conjunction with accompanying drawing, the present invention is described further.
A kind of geotechnical grid retaining wall as shown in Figure 1, 2, its basal layer 1 is stirred by cement and sand gravel and forms, wherein the content of cement is 20%, and the content of sand gravel is 80%, and the diameter of sand is 0.5 ~ 2mm, the diameter of gravel is 2 ~ 50mm, use length 1.5m, strengthening nail based on the reinforcing bar of diameter 12mm, arrange one along basal layer length direction every 2m, arrange one along retaining wall thickness direction every 1m, squeeze into basal layer and play reinforcement effect, basal layer 1 lays geotechnical grid, here the geotechnical grid adopted is of a size of height 20cm, welding torch 80cm, fill out cement-sandy gravel in geotechnical grid and form rigid layer 2, it is identical that its cement-sandy gravel and basal layer 1 use, rigid layer 2 lays geotechnical grid, in geotechnical grid, back-up sand gravel forms bottom gravel drainage blanket 3, bottom gravel drainage blanket 3 upwards lays fill stratum 4 successively, banket in the geotechnical grid of fill stratum 4 and compacting, design degree of compaction need be met, degree of compaction is relevant with type of specifically banketing, to be not less than 0.90 for best, one deck geotechnical grid receding certain distance is often increased from rigid layer 2, until retaining wall top 9, form the gradient being less than 1:0.25, every one deck geotechnical grid is connected with the Bar Anchorage of neighbouring geotechnical grid length 50cm, diameter 12mm, retaining wall the first half fill stratum 4 thickness is the half of the latter half fill stratum 4 thickness, concentrate to prevent, at the variable cross-section place of retaining wall the first half and the latter half, stress occurs, a bar strip 7 has been laid at variable cross-section place (1/2 place that wall is high), fill out cement-sandy gravel in the geotechnical grid of this bar strip 7, its thickness is the half of retaining wall height, in order to increase the strength and stiffness of this place's bar strip 7, this bar strip 7 laying a narrow bar strip 8, fills out cement-sandy gravel in the geotechnical grid of this narrow bar strip 8, wherein aspect ratio bar strip 7 geotechnical grid of the geotechnical grid of narrow bar strip 8 wants high 5cm.
Banketing in the geotechnical grid of fill stratum 4 and compacting, from rigid layer 2, often increase one deck geotechnical grid receding certain distance, until retaining wall top 9, forming the gradient for being less than 1:0.25.See by the data as shown in Fig. 3 (a ~ d), Fig. 4 (a ~ d) and Fig. 5 (a ~ b), this gradient scope is ideal.
At retaining wall height 3/4,7/8, place is respectively arranged with bar strip 7, fills out cement-sandy gravel in the geotechnical grid of bar strip 7, and its thickness is the half of retaining wall height, can strengthen the intensity of retaining wall the first half further.
Be equipped with elongated bar strip 6 at retaining wall height 1/3 place, fill out cement-sandy gravel in the geotechnical grid of elongated bar strip 6, its thickness is that the half of retaining wall height is to whole retaining wall height.As shown in Fig. 3 (a ~ d), proved by theory calculate, lay the frictional force that elongated bar strip 6 can strengthen itself and upper and lower fill stratum 4 at 1/3 place of retaining wall height, reduce the horizontal displacement of retaining wall, increase the stability of retaining wall, improve the safety factor of retaining wall.As shown in figure 11, bar strip thickness (the distance that horizontal direction extends inside retaining wall is shown in figure, by drawing with the ratio of retaining wall height) impact on safety factor, in figure, the ratio of bar strip thickness and retaining wall height is worked as in display is 1.0, that is, when bar strip thickness and retaining wall height equal, safety factor is the highest.
Up lay one deck gravel drainage blanket 5 every 2m at bottom gravel drainage blanket 3, gravel drainage blanket 5 is identical with bottom gravel drainage blanket 3.
Retaining wall top 9 adopts sixteen dirt to fill, and its cross section is U-shaped groove structure, is convenient to rainwater and gets rid of rapidly, prevents from down oozing, as the waterproof measure of retaining wall.
The concrete steps of construction method of the present invention are as follows:
1, according to design drawing, carry out unwrapping wire, excavation, mechanical equivalent of light excavation stops excavation to apart from during substrate design absolute altitude 20 ~ 30cm, with labor cleaning to design altitude, rolls with vibrating roller; Its standard performs with reference to the relevant provision in " Highway Roadbed Construction Technology specification ".On-the-spot test is carried out to bearing capacity of foundation soil, the requirement of bearing capacity of foundation soil should be met.
2, making basal layer; Basal layer is stirred by cement and sand gravel and forms, wherein the content of cement is 20%, the content of sand gravel is 80%, the diameter of sand is 0.5 ~ 2mm, and the diameter of gravel is 2 ~ 50mm, uses length 1.5m, strengthening nail based on the reinforcing bar of diameter 12mm, arrange one along foundation length direction every 2m, retaining wall thickness direction arranges one every 1m, squeezes into basis and plays reinforcement effect.
3, making rigid layer; After basal layer has been constructed, basal layer opens geotechnical grid, be 50cm by length, diameter is that the reinforcing bar of 12mm prolongs retaining wall length direction and arranges one every 2m, one is arranged every 1m along retaining wall thickness direction, opened by geotechnical grid fixing with reinforcing bar, inside fill out cement-sandy gravel, cement-sandy gravel is identical with basal layer.
4, gravel drainage blanket bottom making; Rigid layer opens geotechnical grid, interior back-up sand gravel, as wall body drainage blanket.
5, making fill stratum; Bottom gravel drainage blanket lays geotechnical grid, bankets with loader, loader by importer to fall soil, be aided with artificial leveling simultaneously; Walk in the lattice room that loader bankets after leveling, banket complete to this layer forward successively, forbid loader to roll, destroy geotechnical grid; Carry out degree of compaction and planeness detection in time, degree of compaction is greater than design load, and planeness is less than 2.0cm.Geotechnical grid filler requires even particle size, and maximum particle diameter must not be greater than 10cm; The position small vibrating that distance panel is comparatively near, large roller is not easily close rams compacting.Making second layer fill stratum on the bottom first layer fill stratum that making is complete, making third layer fill stratum on second layer fill stratum is until retaining wall top, every upwards increase one deck geotechnical grid receding certain distance, form the gradient being less than 1:0.25, after every layer of geotechnical grid opens and bankets, all adopt length 50cm, the Bar Anchorage of diameter 12mm connects, in order to strengthen the globality of retaining wall.When making is to retaining wall height 1/2 place, upwards the retaining wall thickness of making is the half of retaining wall the latter half thickness.
6, making gravel drainage blanket; To bottom gravel drainage blanket upwards every 2m making one deck gravel drainage blanket.
7, the elongated bar strip of making; The fill stratum at retaining wall height 1/3 place lays geotechnical grid, inside fills out cement-sandy gravel, the thickness of elongated bar strip is 1/2 ~ 1 of whole retaining wall height.
8, making bar strip and narrow bar strip; At 1/2,3/4,7/8 place of retaining wall height making bar strip respectively, filling concrete sand gravel in the geotechnical grid of bar strip, the thickness of bar strip is the half of retaining wall height.The narrow bar strip of making on the bar strip at 1/2 place of retaining wall height, filling concrete sand gravel in the geotechnical grid of narrow bar strip, its geotechnical grid adopts the height of 25cm.
9, making retaining wall top; Retaining wall top adopts sixteen dirt to fill, and makes U-shaped plough groove type cross section.
The advantage of the geotechnological lattice retaining wall of variable cross-section provided by the present invention:
(1) remarkable in economical benefits, for the geotechnical grid retaining wall of 10 meters high, 100 meters long, a kind of employing traditional structure, retaining wall thickness is 4 meters, H/5,2H/5,3H/5 and 4H/5 (H is that wall is high) is respectively at the bottom of the positional distance wall of bar strip, the thickness of bar strip is respectively 5 meters, 5 meters, 4 meters and 4 meters, needs geotechnical grid 22920m altogether
2, need 60cm length, Φ 12mm connecting reinforcement totally 1375 altogether; A kind of employing new structure, the retaining wall thickness of 5 meters, bottom is 4 meters, and the retaining wall thickness on 5 meters, top is 2 meters, and be respectively H/3, H/2,3H/4 and 7H/8 at the bottom of the positional distance wall of bar strip, bar strip thickness is identical with traditional structure, needs geotechnical grid 18640m altogether
2, need 60cm length, Φ 12mm connecting reinforcement totally 825 altogether, geotechnical grid saving about 19%, reinforcing bar saving about 40%, if the retaining wall thickness of 5 meters, new structure bottom is 4 meters, the retaining wall thickness on 5 meters, top is 3 meters, needs geotechnical grid 21140m altogether
2, geotechnical grid still saves about 8%, reinforcing bar saving about 20%; In addition, it is little that the geotechnical grid due to new structure fills area ratio traditional structure, and due to the workload of slotting reinforcing bar little, so saved labour, reduced labour intensity, and shortened the duration.
(2) impact of reinforcement position: owing to being provided with bar strip at retaining wall H/3 place, for the retaining wall structure of bar strip is set in other positions, safety factor increases, applicant has carried out finite element analysis computation for the retaining wall structure of wall back of the body bar strip diverse location, the computation model of the retaining wall of different bar strip position is as shown in Fig. 6 (a ~ e), the safety factor of retaining wall with bar strip position change as shown in Figure 7, in figure, d represents the position of bar strip and the distance at the bottom of wall, as seen from the figure, bottom the positional distance retaining wall of bar strip during H/3, the safety factor of retaining wall is the highest, as can be seen here, bottom distance retaining wall, H/3 place arranges the frictional force that bar strip strengthens elongated bar strip and the levels soil body, the horizontal displacement of retaining wall can be reduced, enhance the stability of retaining wall entirety, improve its safety factor, retaining wall structure is more reasonable.
(3) the present invention is by arranging bar strip and narrow bar strip at retaining wall upper and lower variable cross-section place and intersection thereof, prevents variable cross-section place stress to concentrate the destruction of causing retaining walls body.
(4) bar strip is set respectively at the place such as 3/4,7/8 of retaining wall height, adds the strength and stability of retaining wall the first half.
A, the impact of layer number of bar, in order to study the impact for the safety factor of retaining wall of the position of reinforced bands and spacing, applicant establishes the model as (a) ~ (f) in Fig. 8 (a ~ h), the safety factor that different condition calculating obtains has listed table 1 in, by known to the analysis of result of calculation, when layer number of bar is equal with thickness, the safety factor of middle and lower part reinforced structure is far above the safety factor of middle and upper part reinforced structure, higher in its safety factor of structure arranging bar strip apart from H/3 and H/2 place bottom retaining wall respectively, be more or less the same with safety factor during the three layers of reinforcement in retaining wall middle and lower part, therefore advise that H/3 and H/2 place arranges bar strip bottom distance retaining wall.Fig. 9 is the impact of the different reinforcement number of plies for safety factor.
The number of plies of table 1 bar strip is for the impact of retaining wall safety factor
Design condition |
Safety factor |
(a) |
1.671 |
(b) |
1.689 |
(c) |
1.69 |
(d) |
1.69 |
(e) |
1.733 |
(f) |
1.729 |
(g) |
1.736 |
(h) |
1.732 |
B, the position of many bar strips is on the impact of retaining wall safety factor: in order to study the impact of different bar strip positions for the safety factor of retaining wall, establish as in Figure 10 (a ~ c) (a), finite element analysis model in (b) and (c), result of calculation shows, a the safety factor under () operating mode is the highest, the result of calculation of different operating mode is as shown in table 2, according to result of calculation, the rational position of bar strip is: the height bottom distance retaining wall is H/3 respectively, H/2, 3H/4 and 7H/8, as can be seen here, the result of the optimum choice that bar strip position required for protection of the present invention is through.
The position of table 2 bar strip is for the impact of retaining wall safety factor
It is to be noted that
The geotechnological lattice retaining wall of variable cross-section provided by the present invention, not necessarily upper and lower respectively accounts for the height of half, can be divided into three sections or multiple, but if the height of general retaining wall is within 12 meters, is normally divided into two sections.And the variable thickness of upper half is the half of next half thickness surely, if within 10 meters, the thickness of upper half is the half of next half thickness usually, if 12 meters, the thickness of upper half is 3/4 of next half thickness usually.
The thickness of elongated bar strip is not that must to equal wall high, and thickness also can close to wall height.The numerical value such as other ratios mentioned in same the present embodiment are also interpreted as being set as that its approximate number also can realize, and the numerical value just explicitly pointed out is most preferred embodiment.