CN115288162B - Reinforcing method for soft soil foundation filling side slope - Google Patents
Reinforcing method for soft soil foundation filling side slope Download PDFInfo
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- CN115288162B CN115288162B CN202210873772.0A CN202210873772A CN115288162B CN 115288162 B CN115288162 B CN 115288162B CN 202210873772 A CN202210873772 A CN 202210873772A CN 115288162 B CN115288162 B CN 115288162B
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Classifications
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- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
- E02D17/00—Excavations; Bordering of excavations; Making embankments
- E02D17/20—Securing of slopes or inclines
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- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
- E02D17/00—Excavations; Bordering of excavations; Making embankments
- E02D17/20—Securing of slopes or inclines
- E02D17/207—Securing of slopes or inclines with means incorporating sheet piles or piles
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- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06F—ELECTRIC DIGITAL DATA PROCESSING
- G06F30/00—Computer-aided design [CAD]
- G06F30/20—Design optimisation, verification or simulation
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- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06Q—INFORMATION AND COMMUNICATION TECHNOLOGY [ICT] SPECIALLY ADAPTED FOR ADMINISTRATIVE, COMMERCIAL, FINANCIAL, MANAGERIAL OR SUPERVISORY PURPOSES; SYSTEMS OR METHODS SPECIALLY ADAPTED FOR ADMINISTRATIVE, COMMERCIAL, FINANCIAL, MANAGERIAL OR SUPERVISORY PURPOSES, NOT OTHERWISE PROVIDED FOR
- G06Q10/00—Administration; Management
- G06Q10/06—Resources, workflows, human or project management; Enterprise or organisation planning; Enterprise or organisation modelling
- G06Q10/063—Operations research, analysis or management
- G06Q10/0639—Performance analysis of employees; Performance analysis of enterprise or organisation operations
- G06Q10/06393—Score-carding, benchmarking or key performance indicator [KPI] analysis
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- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06F—ELECTRIC DIGITAL DATA PROCESSING
- G06F2119/00—Details relating to the type or aim of the analysis or the optimisation
- G06F2119/14—Force analysis or force optimisation, e.g. static or dynamic forces
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
- Y02A10/00—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE at coastal zones; at river basins
- Y02A10/23—Dune restoration or creation; Cliff stabilisation
Abstract
The invention provides a reinforcing method for a soft soil foundation filling side slope. The reinforcing method comprises the steps of firstly adopting an improved process to perform dynamic compaction replacement pier reinforcement on a soft soil foundation, replacing the soft soil of the foundation with broken stones to form a broken stone replacement pile composite foundation so as to enhance the bearing capacity of the foundation, accelerating the drainage consolidation process of a soft soil layer, obviously improving soft soil parameters, secondly performing superfilling reinforcement on the broken stone soil of a slope body of a backfilled slope, and grading slope cutting, wherein the surface soil of the foundation is configured with planting soil for greening the slope surface of the slope. The method has the advantages of low engineering cost, little environmental pollution, full utilization of site crushed stone soil, waste recycling and good economic and social benefits.
Description
Technical Field
The invention relates to the technical field of slope reinforcement, in particular to a method for reinforcing a soft soil foundation filled slope.
Background
In recent years, the country proposes a double-carbon target, a plurality of industrial enterprises improve new processes, the process is gradually changed to green, a plurality of production bases are moved from urban areas to mountain areas, the foundation construction scale of new factories is large, the field area is large, a large amount of land is needed to solve the land requirement, and large-area high-excavation low-filling areas exist in the field. In the excavated area, a large amount of loose gravel soil is generated in the process of leveling the earthwork of the construction site, and the soil body is not easy to compact, so that the excavation and transportation engineering amount is large, and the construction period is long. In the filling area, deep soft soil is distributed in the valley area with lower topography, so that the soft soil has high thixotropic property and high rheological property, is easy to deform under the action of load, and is easier to deform under the condition of long-time uninterrupted external force and gravity.
Therefore, the problem exists that soft soil foundations fill the side slopes, and if the soft soil foundations are not reinforced, the foundation bearing capacity is difficult to meet the requirement due to the fact that the ultra-high filling load is large. The high filling side slope of the gravelly soil formed in the field is not easy to support, loose in soil quality and compact, and the supporting structure is easy to be adversely affected in the compaction construction process.
The traditional treatment method is that a bored pile is adopted as an anti-slide pile, a slope toe foundation needs to bear larger horizontal thrust, the pile bottom of the anti-slide pile is anchored in a hard rock soil layer, and engineering investment is huge. The cement soil mixing pile is adopted for construction, the treatment area is large, the engineering investment is large, and the treatment time is long. If the designed and reinforced gravel soil high-fill side slope is not subjected to design and reinforcement treatment, a one-time backfilling mode is adopted, so that the side slope instability is extremely easy to be caused, and the safety of construction and operation of a road on the top of the side slope and an industrial factory building is influenced. Therefore, the selection of an effective treatment scheme is particularly important, the soft soil foundation is reasonably treated, and meanwhile, the problems of stockpiling, outward transportation and slope greening of gravels in the excavated area in the field are solved. The present invention has been made in order to solve the series of problems.
Disclosure of Invention
The invention aims to provide a reinforcing method for a soft soil foundation filling side slope, which aims to solve the problems of high construction cost, high reinforcing treatment difficulty, low drainage consolidation speed, piling up and transporting out of broken stone soil in a excavated area in a field, reduce the treatment cost, avoid secondary pollution, and simultaneously use foundation surface soil for configuring slope greening planting soil and avoid an outer earth transporting source.
In order to achieve the technical aim, the invention provides a soft soil foundation filling side slope reinforcing method, which is characterized by comprising the following specific steps:
(1) Obtaining physical and mechanical property indexes of a soft soil slope soil layer according to geological investigation, calculating an untreated soft soil slope stability safety coefficient according to a simplified Chinese zodiac method, determining a sliding arc coverage area which cannot meet the slope stability safety coefficient, and determining the depth and the plane processing range of a soft soil reinforcement area; the slope stability safety factor F s The calculation formula of (2) is as follows:
wherein: f (F) s -a soft soil slope stability safety factor;
m θi -calculating coefficients;
l i length of the ith soil strip bottom slip arc
G i -gravity of the ith soil strip, unit: kN;
G bi -i-th soil strip vertical external force, unit: kN;
c i -i-th soil layer cohesive force, unit: kPa;
-a soft soil slope soil layer internal friction angle;
θ i -the inclination of the bottom slip surface of the ith soil strip;
(2) And (3) carrying out dynamic compaction test on broken stone and filled soil of a slope: selecting a representative field in the soft soil reinforcement area determined in the step (1), performing a slope crushed stone soil filling dynamic compaction test, wherein the area of the test area is not less than 20mx and 20m, and performing a dynamic sounding test on the tamping test area when the tamping of the test area meets the sedimentation requirement to obtain a shear strength index c of the crushed stone soil filling dynamic compaction test area g 、
(3) Dynamic compaction displacement pier test: pile forming test is carried out in the soft soil reinforcement area determined in the step (1) before construction, construction technology and parameters of the dynamic compaction replacement piers are determined, the number of test piles is not less than 2, the pile diameter of the dynamic compaction replacement piers is 0.5-1.2 m, the pile depth is at least 1-2 m penetrating through a sliding arc surface, the pile depth is not more than 20m, and the pile depth is determined in the following steps ofWhen the tamping of the test pile meets the sedimentation requirement, carrying out a dynamic sounding test on the dynamic compaction displacement pier test pile to obtain a shear strength index c of the test dynamic compaction displacement pier test pile p And
(4) Setting the replacement rate m of the dynamic compaction replacement pier x And m is x The value range is as follows: 5% -30%; and will set m x Value, shear strength index c of dynamic compaction replacement pier determined according to test in step (2) p Andshear strength index c of soil between piles in dynamic compaction displacement pier treatment area determined in geological survey s And->Calculating the shear strength index c of the composite foundation in the dynamic compaction replacement pier treatment area according to the following formula sp And->
c sp ＝m x c p +(1-m x )c s ③
Wherein: c p -dynamic compaction displacement pier cohesive force, unit: kPa;
-dynamic compaction displacement pier internal friction angle, unit: a degree;
c s -cohesive force of soil between piles in the dynamic compaction displacement pier treatment area, unit: kPa;
-friction angle of soil between piles in the dynamic compaction displacement pier treatment area, unit: a degree;
c sp -composite foundation cohesion, unit: kPa;
-composite foundation internal friction angle, unit: a degree;
m x -a set displacement rate of the dynamic compaction displacement pier;
(5) The shear strength index c of the composite foundation calculated in the step (4) is calculated sp Andchecking the stable safety coefficient of the composite foundation in the formulas (1) and (2) in the step (1), and setting the dynamic compaction replacement pier replacement rate m when the stable safety coefficient of the composite foundation meets the slope stable safety coefficient x The value is the replacement rate m of the dynamic compaction replacement pier in the composite foundation;
(6) According to the calculated displacement rate m of the dynamic compaction displacement pier in the step (5), the pile diameter d obtained by pile testing in the step (2), the spacing s of the dynamic compaction displacement pier is calculated according to different pile distribution modes, and a construction design drawing of the dynamic compaction displacement pier is drawn according to the calculation result;
when square piles are distributed: from the following componentsObtain->
When the regular triangle piles are distributed: from the following componentsObtain->
(7) Leveling the site, burying a pore water pressure gauge near a soft soil foundation reinforcing area outside the slope toe, and measuring a pore water pressure reference value of the foundation before the construction of the dynamic compaction replacement pier;
(8) Constructing dynamic compaction replacement piers according to the construction design drawing of the dynamic compaction replacement piers in the step (6) aiming at the soft soil foundation reinforcement area outside the slope toe, constructing the dynamic compaction replacement piers at intervals, and extruding soft soil out of the range of the reinforcement area outside the slope from inside the slope to outside the slope; the construction adopts an impact expansion hammer and a column hammer, wherein the impact end of the impact expansion hammer is conical, and the column hammer is a cylindrical impact hammer; after the construction machine is in place, firstly, tamping a construction point by adopting a punching hammer for multiple times to form a hole with the diameter matched with the diameter of the hammer body, wherein the depth is the design depth of the dynamic compaction replacement pier, then, replacing the dynamic compaction replacement pier column hammer, filling the hole with gravelly soil filler in layers, tamping the gravelly soil filler in the hole by using the column hammer after each filling until the gravelly soil filler reaches a construction operation surface;
(9) Monitoring pore water pressure through a pore water pressure gauge buried in advance, fully tamping a field surface layer once after the pore water pressure is dissipated, wherein the tamping energy is 1500-2000 kN.m, and finishing the treatment of the soft soil foundation outside the toe;
(10) The design of a side slope is carried out in a multi-stage manner according to a slope rate method, the width of a graded pavement is controlled to be not less than 2m, the backfill-planning side slope is treated in a layered manner according to the designed height of the side slope, the thickness of each layer of the gravel soil to be treated is determined, and the gravel soil filling and dynamic compaction construction is carried out on the side slope according to the parameters of the step (3) of the slope body gravel soil filling dynamic compaction test;
(11) After the gravel soil filling dynamic compaction construction of the slope is completed, the backfilled slope is subjected to slope cutting and slope greening, and a slope drainage system is constructed.
The invention further adopts the technical scheme that: calculating an untreated soft soil slope stability safety coefficient through slope processing software in the step (1), analyzing a sliding arc coverage area which cannot meet the safety coefficient by checking the passing position of the least favorable sliding surface, and determining the depth and the plane processing range of a soft soil reinforcement area; the slope processing software comprises Slide software, positive rock-soil processing software or Nanjing coulomb software; and the dimension and stratum distribution of the side slope end face are obtained through geological mapping and investigation,obtaining physical indexes and mechanical indexes of each soil layer, inputting the investigation parameters into slope processing software, establishing a two-dimensional slope model, automatically searching sliding arcs by the software, and performing strip division on the slope above the sliding arcs to directly obtain the length l of the sliding arc of the ith soil strip bottom of the slope i Gravity G of ith soil strip i External force G in vertical direction of ith soil strip bi I-th foundation soil layer cohesive force c i Inclination angle theta of ith soil strip bottom sliding surface i And calculating the slope stability coefficient through formulas (1) and (2).
The invention has the preferable technical scheme that: and (3) determining the treatment depth reaching the dynamic compaction displacement pier in the dynamic compaction displacement pier test in the step (2), the required weight, hammer length and drop distance of the hammer, and determining the layered filling quantity and the tamping times through a process test.
The invention has the preferable technical scheme that: in the step (3), in the dynamic compaction test of the broken stone filling soil of the slope body, parameters such as the dynamic compaction energy, the compaction point spacing, the compaction times, the compaction pass number, the effective reinforcement depth and the like are determined by combining the test compaction, and the corresponding single-impact compaction energy is selected:
the invention has the preferable technical scheme that: calculating the amount of soil tillage required for covering and leveling the slope before leveling the site in the step (7), and excavating earth surface soil tillage correspondingly during construction; removing barriers after leveling the field, paying off, defining a control axis, piling the side line of the field and marking, backfilling loose gravel soil on the original ground to form a crust layer on the field surface layer, and facilitating mechanical equipment to enter the field for construction.
The invention has the preferable technical scheme that: in the step (8), when the punching and expanding hammer is used for punching construction points for a plurality of times, and hole collapse occurs in the punching and expanding hammer hole, the hammer can be lifted to repeatedly impact to the designed depth, and finally a hole with the diameter matched with the diameter of the hammer body is formed; the step (8) of dynamic compaction replacement piers is to divide the spaced pile positions into two groups for construction, after the first group of construction is completed, pore water pressure values of a site are measured by using a pore water pressure gauge which is buried in advance, and after the pore water pressure is dissipated, the construction is performed on the second group of jump positions from the head; the impact expansion hammer is raised to a certain height during construction, then falls freely to impact the hole, and is tamped for multiple times, so that a hole with the diameter of the hammer body and the diameter of the ground is formed, and the hole forming depth is 12-13 m; the average compaction coefficient of the filling materials in the pile body of the dynamic compaction replacement pier is not less than 0.98, the number of times of compaction is accumulated to be 1.5-2.0 times of the designed pier length along with the filling of the dynamic compaction replacement pier, and the average compaction amount of the last two strokes is not more than 250mm; the dynamic compaction replacement pier filling material in the step (8) and the filling slope body material in the step (10) are loose gravelly soil generated in the process of leveling the earthwork of a construction site, the gravels with larger particles need to be crushed for the second time, and the particle content of the gravels with the particle size of more than 300mm is not more than 30%.
The invention has the preferable technical scheme that: in the slope backfilling of the step (10), during backfilling of the first grade slope, the gravels are superfilled within 5m of the top line of the filled slope, so that the whole slope can be reinforced by dynamic compaction; marking the position of the tamping point in the first time, measuring the elevation of the field, finishing the tamping of all the tamping points in the first time, filling up the tamping pit by using a bulldozer, and measuring the elevation of the field; after a specified interval time, the whole ramming times are completed according to the steps, and finally, low-energy full ramming is adopted; detecting after each time of tamping, and sequentially completing the piling and dynamic tamping of a second grade slope, a third grade slope and the like according to the steps after the requirements are met, so that the whole slope body can be reinforced; and (3) when the design elevation from the dynamic compaction surface to the slope top is 40-60 cm, two layers of geogrids are paved at intervals, after each layer of geogrids is paved, a middle sand cushion layer is paved on the surface of each layer of geogrids, then uniform gravel soil is paved, and layering rolling is carried out.
The invention has the preferable technical scheme that: in the step (11), the slope is cut from top to bottom in layers, and the slope is subjected to greening by adopting a bulldozer and manual trimming, and after finishing the slope cutting, the slope surface of the side slope is greened; the slope greening is specifically realized by digging a slope with a soil coverage value of the ground surface, wherein the coverage thickness is 20 cm-25 cm, sprinkling water for wetting, then paving a three-dimensional net along the slope from top to bottom, and fixing the net pad to the slope from top to bottom by using U-shaped nails and steel nails, wherein the slope top and the slope foot are respectively fixed according to the design requirement; after the three-dimensional net is fully paved and fixed, the soil and fertilizer on the surface of the land are sown from the top of the slope to the bottom of the slope, and the thickness of the soil is sown to cover the net; applying a base fertilizer and a soil conditioner before sowing, sowing grass and irrigating seeds in sections, checking whether the sowing is missed or not at any time, watering in time after sowing, covering an earth work film, and watering in time for maintenance until the survival rate is not lower than 90% when grass is planted into a lawn, and entering into normal maintenance after the lawn is formed; the side slope drainage system is combined with the factory side slope drainage system; and finally, monitoring slope engineering, and monitoring horizontal displacement and vertical displacement of the slope top and slope surface deformation.
The invention has the preferable technical scheme that: the equipment used for the dynamic compaction replacement piers and the dynamic compaction in the step (2), the step (3), the step (8), the step (9) and the step (10) are the same equipment, and comprise a crane, a cable and a unhooking device, and when the dynamic compaction replacement piers are constructed to pre-form holes, the unhooking device is connected with a punching and expanding hammer; when the filling material in the pier holes is replaced by the dynamic compaction, the unhooking device is connected with the column hammer; when the slope body is rammed dynamically, the unhooking device is connected with the rammer; and setting a dynamic compaction portal frame on the basis of a dynamic compaction machine when constructing the dynamic compaction replacement pier, and stabilizing the crane.
The invention has the preferable technical scheme that: the base fertilizer and the soil conditioner are applied before sowing during slope greening, wherein the base fertilizer mainly comprises nitrogenous fertilizer, phosphate fertilizer and potash fertilizer, the proportion is 15:8:7, and the proportion is 35g/m 2 Administered right and left.
The processing depth of the dynamic compaction replacement pier in the prior art is generally not more than 10m, in order to achieve larger depth, the invention adopts an improved process, a punching and expanding hammer is used for forming holes, the hammer head of the punching and expanding hammer is conical, the grounding pressure is high, the hole is easy to impact, the hole forming depth in a soft soil stratum can reach 12-16 m, after the hole is formed, the filling is compacted, in order to prevent the conical hammer head from being damaged by compacted broken stone, the dynamic compaction replacement pier column hammer is replaced, the shape of the ramming hammer is cylindrical, the diameter of the ramming hammer is equal to that of the punching and expanding hammer, and the broken stone filling in the filling hole is compacted. If the depth of the soft soil layer to be treated exceeds 16m, the earth surface can be covered with the soil layer to be excavated, a shallow foundation pit is formed, the excavated soil layer can be piled aside, slope greening cultivation soil is reserved, 0.5-1.0 m thick gravels are backfilled in the foundation pit to serve as a construction platform, dynamic compaction replacement piers are constructed in the foundation pit, and gravels are backfilled in the foundation pit after construction is completed, so that the requirement that the deep treatment of the soft soil foundation is more than 16m is met.
The dynamic compaction replacement pier and the equipment used by the dynamic compaction are the same equipment, the equipment is single and simple, the construction equipment is low in cost, the phenomenon of cross operation of various large-scale equipment is avoided, and the construction can be performed even under the condition of narrow places. The tamping energy of the dynamic compaction replacement pier is preferably increased along with the depth of the tamping hole, the tamping energy is gradually increased from a low energy level to a high energy level, and in order to prevent the high-energy-level dynamic compaction from causing the overturning of a crane, a dynamic compaction portal frame can be set on the basis of a dynamic compactor to stabilize the crane. The construction of the middle column hammer impact expansion method has large impact energy, is easy to bulge the ground, and causes the looseness of the surface layer piles and the soil between the piles, thereby reducing the treatment effect, adopting the jump hole construction to reduce the super pore water pressure in the soft soil of the foundation and fully discharging the super pore water in the soft soil. The invention can perform dynamic compaction on the whole slope in place, and the super-filled gravel soil is filled in a certain range outside the slope top line of the filled slope, and the super-filled width is not less than 5m, so as to meet the construction requirement of dynamic compaction on the slope top line, strengthen the whole slope and enhance the anti-slip performance of the slope after the slope is cut. In the invention, two layers of three-way geogrids are paved within the depth range of 50cm at the top of a slope, the creep performance is required to be good, the ultraviolet-proof capability is required to be realized, the carbon black content is required to be not less than 2%, the particle size of broken stones is required to be controlled to be less than 150mm in order to prevent the stones from damaging the geogrid, the excavated stones are required to be smashed, and the static pressure of a smooth roller is required to be realized within the depth range of 50cm at the top of the slope. The invention adopts a method of sowing grass and irrigating seeds in a segmented way to complete a method of sowing one segment, so as to avoid the situation of uneven sowing or missing sowing due to the fact that the mechanical equipment with the side slope length can not reach.
The invention has the beneficial effects that:
(1) The invention provides a calculation method for soft soil foundation filling slope reinforcement, which determines the depth and plane processing range of a soft soil reinforcement area, and parameters such as pile length and distance of a dynamic compaction replacement pier, grading of a slope body, reinforcement depth and the like, and guides engineering practice through theoretical calculation results, thereby playing an important role.
(2) The dynamic compaction replacement pier composite foundation is successfully applied to the treatment of a soft soil foundation filling side slope, and has the advantages of economy, cheapness, technical controllability, strong operability, high comprehensive economic benefit and the like compared with an anti-slide pile and a cement mixing pile; the shear strength index of the foundation soft soil can be effectively improved, a large amount of broken stone soil generated by excavating mountain bodies can be digested and treated, engineering freight cost generated by waste slag outward transportation is reduced, and the composite foundation strength formed by the dynamic compaction replacement pier and soil between the piers can meet design and specification requirements.
(3) The foundation bottom of the slope toe is composed of dynamic compaction replacement piers, because the gravel piles are subjected to external load action to move outwards in the formation process of the dynamic compaction replacement piers, the gravel produces extrusion and vibration actions on the transverse soil body, so that the positions of soil particles around the gravel piles are rearranged and tend to be compact, part of the gravel enters the surrounding soft soil layer due to the external force action in the pile forming process, the structure and the mechanical properties of the soil body are changed, the load pressure is reduced by increasing a stress area, after the pile is formed, the gravel piles form a good drainage structure, the foundation shear strength can be improved, the water removal of the soft soil is accelerated, the sedimentation and consolidation time is shortened, and the foundation has certain waterproof and waterlogging-preventing capabilities.
(4) According to the invention, the crushed stone soil generated by site leveling is fully utilized for dynamic compaction construction, the backfill thickness and the superfilling width of the crushed stone soil can be designed in a layered manner according to the dynamic compaction energy level, the compactness of the crushed stone soil of the slope body is improved, and the overall stability of the slope can meet the design requirement.
(5) The invention can superfilling the gravels in a certain range outside the slope surface line of the filled slope, can meet the construction requirement of dynamic compaction at the slope top line, and solves the technical problem that the gravels of the high filled side slope of the gravels are not easy to compact in a certain range from the slope top line; the anti-slip performance of the slope after slope cutting can be enhanced, the platform formed by super-filling gravel soil in a layered excavation mode can enable construction to be more convenient from top to bottom in a layered sectional slope cutting mode, the construction difficulty of slope repairing is reduced, and the construction safety of high-filling gravel soil slope supporting is guaranteed.
(6) The soft soil foundation filled side slope has high stability after being reinforced, solves the problem of piling up and transporting out broken stone soil in the excavated area in the field, reduces the treatment cost, does not cause secondary pollution, and simultaneously uses the soil planted on the surface layer of the foundation to configure planting soil so as to avoid the source of transporting soil outwards; the reinforcing method reduces environmental pollution, changes waste into valuable, has high utilization rate, and has better economic and social benefits.
Drawings
FIG. 1 is a schematic diagram of calculation of circular arc sliding stability of a slope before reinforcement in the invention;
FIG. 2 is a plan view of the process area of the dynamic compaction displacement pier in an embodiment;
FIG. 3 is a cross-sectional view of a dynamic compaction displacement pier;
FIG. 4 is a schematic diagram of a punching and expanding hammer to a dynamic compaction replacement pier punching and expanding hole in an embodiment;
FIG. 5 is a schematic diagram of a column hammer in an embodiment for dynamic compaction of a dynamic compaction replacement pier;
FIG. 6 is a cross-sectional view of a dynamic compaction of a slope in an embodiment;
FIG. 7 is a schematic view of a dynamic compaction of a slope in an embodiment;
FIG. 8 is a construction completion view of a soft soil foundation filling side slope in an embodiment;
FIG. 9 is a schematic diagram of calculation of the arc sliding stability of the slope after the slope is fixed in the embodiment;
in the figure: 1-a crawler crane, 2-a cable, 3-a unhooking device, 4-a punching and expanding hammer, 5-a column hammer, 6-a dynamic compaction replacement pier, 7-a slope line to be repaired, 8-a dynamic compaction area, 9-an ultra-digging area, 10-an original topography line, 11-a dynamic compaction replacement pier impact hole, 12-a geogrid, 13-a slope net hanging grass planting structure, 14-a pavement drainage ditch,
Detailed Description
In order that the manner in which the invention can be understood in light of the above-recited features and advantages of the invention, a more particular description of the invention will be rendered by reference to specific embodiments thereof which are illustrated in the appended drawings. Figures 1 through 6 are drawings of embodiments, which are drawn in a simplified manner, for the purpose of illustrating embodiments of the invention in a clear and concise manner. The following technical solutions presented in the drawings are specific to embodiments of the present invention and are not intended to limit the scope of the claimed invention. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
Aiming at the problems existing in the prior art, the invention provides a safe construction method for earth and stone excavation filling and side slope supporting engineering, and the invention is described in detail below with reference to the accompanying drawings.
The invention is further described below with reference to the accompanying drawings. The following examples are only for more clearly illustrating the technical aspects of the present invention, and are not intended to limit the scope of the present invention.
As shown in fig. 4, 5 and 6, the marks 1 to 9 are respectively shown as: the crawler crane comprises a crawler crane body 1, a cable 2, a unhooking device 3, a punching and expanding hammer 4, a column hammer 5, a dynamic compaction replacement pier 6, a slope line 7 to be repaired, a dynamic compaction area 8 and an superfilling area 9. The construction process of the present invention will be further described with reference to examples with reference to the accompanying drawings.
In the embodiment, aiming at the land units of the low-lying valley of a certain construction site, the topography is complex, the north part and the west part of the site are higher, the east part and the south part are lower, and the topography is more undulating. And leveling the field according to the design elevation and the principle of high digging and low filling. The foundation soil layer is distributed with silt soft soil in the areas with lower features on the east side and the south side, and the areas form a filling side slope after being leveled according to the designed elevation. The site strata can be divided into 3 engineering geologic layers according to the characteristics of the site strata. The engineering geological features of each rock and soil layer from top to bottom are as follows:
layer (1): plain fill (Q) 4 ml ) Gray, off-white, slightly wet, loose, highly compressible, mainly powdery clay.
Layer (2): muddy silty clay (Q) 4 l ) The soft plastic is mainly gray and black, and the few plastic flows. Contains organic matters, has light fishy smell, low dry strength, moderate toughness, slight luster and slight reaction during shaking.
Layer (3): powdery clay (Q) 4 al+pl ) Brown yellow, tan. Soft plastic is mainly, part of the soft plastic is plastic, the dry strength is high, no shaking reaction exists, the soft plastic is slightly glossy, the cutting surface is smooth, and the soft plastic is mainlyThe coating consists of clay particles and powder particles, and has unobvious lamellar characteristics.
Layer (4): stroke fossil limestone (T1), biological structure, block structure, aphanitic structure, calcareous cementation. The rock mass is more complete and contains more calcite veins and quartz veins. The hardness degree of the rock belongs to the harder rock, and the basic quality grade III of the rock mass is grade III.
Table 1 is a table of parameters for designing physical and mechanical indexes of the rock and soil for each soil layer
The concrete steps of the reinforcement treatment for the side slope are as follows:
(1) According to the physical and mechanical property indexes of the main soil layer revealed by the geological survey, adopting a simplified Chinese zodiac method, calculating an untreated slope stability coefficient through slope software (Slide, theoretical positive rock soil and Nanjing coulomb),
the slope stability safety factor F s The calculation formula of (2) is as follows:
wherein: f (F) s -a soft soil slope stability safety factor;
m θi -calculating coefficients;
G i -gravity of the ith soil strip, unit: kN;
G bi -i-th soil strip vertical external force, unit: kN;
c i -i-th soil layer cohesive force, unit: kPa;
-a soft soil slope soil layer internal friction angle;
θ i -inclination of the bottom slip surface of the ith soil strip.
As shown in FIG. 1, the safety coefficient is calculated to be 1.097<1.35, and the safety and stability coefficient requirements of the primary permanent side slope are not met. Checking the passing position of the least favorable sliding surface, analyzing a sliding arc coverage area which cannot meet the safety coefficient at the deepest position of about 10.5m below the ground surface, and determining the depth of a soft soil reinforcement area to be about 12m and the width of a plane processing range to be about 48m; the plan view of the processing range of the dynamic compaction displacement pier 6 is shown in fig. 2.
(2) Dynamic compaction test of slope crushed stone: selecting a representative site from the slope surface of the soft soil reinforcement area determined in the step (1), performing a slope body broken stone filling dynamic compaction test, wherein the area of the test area is not less than 20mx and 20m, and performing a dynamic sounding test on the tamping test area when the tamping of the test area meets the sedimentation requirement to obtain a shear strength index c of the broken stone filling dynamic compaction test area g 、
(3) Dynamic compaction replacement pier 6 test: performing pile forming test in the soft soil reinforcement area determined in the step (1) before construction, determining construction process and parameters of the dynamic compaction replacement piers, wherein the number of test piles is not less than 2, the pile diameter of the dynamic compaction replacement piers is 0.5-1.2 m, determining that the treatment depth reaching the dynamic compaction replacement piers 6 is about 12m, and obtaining the shear strength index c of the test dynamic compaction replacement pier test pile through heavy dynamic detection test when the tamping of the test pile reaches the sedimentation requirement p ＝0kPa，
(4) Setting the replacement rate m of the dynamic compaction replacement pier x And m is x The value range is as follows: 5% -30%, optimally 10% -20%; and will set m x And (3) measuring the shear strength index c of the dynamic compaction replacement pier determined according to the test in the step (2) p Anddynamic compaction determined in geological surveyShear strength index c of soil between piles within depth range of replacement pier s And->The shear strength index c of the composite foundation after the dynamic compaction replacement piers and the crushed stone filled dynamic compaction soil layer are combined is calculated by the following formula sp And->
c sp ＝m x c p +(1-m x )c s ③
Wherein: c p -dynamic compaction displacement pier cohesive force, unit: kPa;
-dynamic compaction displacement pier internal friction angle, unit: a degree;
c s -cohesive force of soil between piles in the depth range of the dynamic compaction replacement pier, wherein the cohesive force is as follows: kPa;
-dynamic compaction displacement of the internal friction angle of the soil between piles in the depth range of the pier, unit: a degree;
c sp -composite foundation cohesion, unit: kPa;
-composite foundation internal friction angle, unit: a degree;
m x -a set displacement rate of the dynamic compaction displacement pier;
(5) The shear strength index c of the composite foundation calculated in the step (4) is calculated sp Andchecking the stable safety coefficient of the composite foundation in the formulas (1) and (2) in the step (1), and setting the dynamic compaction replacement pier replacement rate m when the stable safety coefficient of the composite foundation meets the slope stable safety coefficient x The value is the replacement rate m of the dynamic compaction replacement pier in the composite foundation, namely m=0.20. The strength index values for which the foundation satisfies the stability safety factor are thus obtained as shown in table 2:
table 2 shows the strength index c of the composite foundation sp 、Value of
Square pile laying is carried out byObtain->Assuming that the pile diameter d of the dynamic compaction replacement pier 6 is 1.2m, s=2.4m is obtained. Designing pier length to be 12m, wherein the pier body material adopts hard coarse particle materials such as block stones, broken stones and the like with good grading, and the particle content with the particle diameter of more than 300mm is not more than 30%; and drawing a construction design drawing of the dynamic compaction replacement pier according to the calculation result.
(6) Before construction, calculating the amount of soil planted in the soil needed for covering and leveling the slope, and digging out the soil on the surface, leveling the field and removing the barrier.
(7) Paying off, defining a control axis and a piling site side line, and marking. Loose gravel soil is backfilled on the original ground, so that a crust layer is formed on the surface layer of the field, and mechanical equipment can enter the field for construction conveniently.
(8) And (3) embedding a pore water pressure gauge near the soft soil foundation reinforcing area outside the slope toe, and measuring a pore water pressure reference value of the foundation before the construction of the dynamic compaction replacement pier 6.
(9) As shown in fig. 4, the construction machine is in place, and the column hammer is aligned to the pile position according to the diameter, pile spacing, pile length and reinforcement plane range of the dynamic compaction displacement pier 6 calculated in step (5). As shown in fig. 4, the impact end of the impact expansion hammer is conical and is used for ramming the ground for multiple times, so that a hole with the diameter approximately equal to the diameter of the hammer body is formed on the ground. And then replacing a column hammer of the dynamic compaction replacement pier 6, wherein the column hammer is a conical impact hammer, as shown in fig. 5, then using a hammer body to tamp the filler in the hole, lifting the hammer body to continuously add part of the filler into the hole after tamping, using the hammer body to tamp the filler in the hole, gradually increasing the point tamping energy from 800kN.m to 18000kN.m, and carrying out single-point tamping with the tamping, wherein the number of times of single-point tamping is not less than 10, and is determined by field test, the accumulated tamping sinking amount of the number of times of tamping is (1.5-2.0) times of the designed pier length, and the average tamping sinking amount of the last two strokes is not more than 250mm. Repeating the steps for a plurality of times until the filler reaches the construction working surface.
(10) And (3) shifting the construction machine, adopting an interval construction mode, repeating the steps to construct the next pile according to the construction from the inside of the slope to the outside of the slope, and extruding the soft soil out of the range of the reinforcing area outside the slope.
(11) Measuring the pore water pressure value of the site by using a pre-buried pore water pressure gauge, and constructing the dynamic compaction displacement pier 6 from the beginning to the jumping position after the pore water pressure is dissipated;
(12) And continuously monitoring the pore water pressure, fully tamping the field surface layer once after the pore water pressure is dissipated, fully tamping the pier top, wherein the tamping energy is 1500-2000 kN.m, and finishing the soft soil foundation treatment.
(13) The slope design is carried out in multiple stages according to a slope rate method, and the width of the graded pavement is 3m. As shown in fig. 6 and 7, the design height of the side slope is about 20m, the backfill-like side slope is treated in 3 layers, the thickness of each layer of the crushed stone soil to be treated is determined to be 7m, and the depth of dynamic compaction of the upper layer and the lower layer is overlapped by 0.5-1.0 m; backfilling the first grade slope, wherein the slope height is 7m, and superfilling gravels and stones in a certain range outside the slope top line of the backfilled slope so as to meet the construction requirement of dynamic compaction at the slope top line. Marking the position of the tamping point in the first time, measuring the elevation of the field, and carrying out dynamic compaction and compaction for the tamping energy of 4000kN.m for one time. The number of the spot tamping passes is 2, the distance between the tamping points is 6.0m, the spot tamping is 4000kN.m in the first pass, the spot tamping is 4000kN.m in the second pass, and the number of the spot tamping is 6-8; the ramming is carried out for 1 time, the ramming energy is 2000kN.m, the ramming energy is 3, and the hammer diameter is overlapped by 1/4. The average ramming settlement of the last two dynamic rammers is not more than 100mm. Filling up the tamping pit by using a bulldozer, and measuring the elevation of the field; after a prescribed interval, the whole number of ramming passes is completed according to the steps, and finally, low-energy full ramming is adopted.
(14) And detecting after each time of tamping, and sequentially completing the piling and dynamic tamping of the second grade slope, the third grade slope and the like according to the steps after the requirements are met, so that the whole slope body can be reinforced.
(15) When the design elevation from the dynamic compaction surface to the slope top is 50cm, respectively paving a layer of geogrid at the depths of 25cm and 50cm, adding up to 2 layers, after the geogrid is paved, paving a middle sand cushion layer of 50mm on the surface of the geogrid, then paving uniform gravelly soil, and carrying out layered rolling. Thus controlling uneven settlement of the slope top.
(16) As shown in fig. 8, the slope is cut from the upper and lower layers, and the slope is manually trimmed by using a bulldozer. After finishing the slope cutting, greening the slope surface of the side slope, covering the ground surface soil excavated in the step (1) with the soil 20cm thicker than the leveled slope surface, sprinkling water for wetting, paving a three-dimensional net along the slope surface from top to bottom, and fixing the net pad with U-shaped nails and steel nails from top to bottom to enable the net pad to be attached to the slope surface; the slope top and the slope foot are respectively fixed according to the design requirement; after the three-dimensional net is fully paved and fixed, the soil and fertilizer on the surface of the land are manually sown from the top of the slope to the bottom of the slope, and the thickness of the soil is sprayed to cover the net. Applying a base fertilizer and a soil conditioner before sowing, artificially sowing grass and irrigating seeds in sections, checking whether the grass and the seeds are not sowed at any time, timely watering after sowing, covering an earth work film, timely watering and maintaining until grass planting forms a lawn, and entering normal maintenance after the lawn is formed, wherein the survival rate is required to be not lower than 90%.
(17) The drainage system for building the side slope is combined with the drainage system for the side slope of the factory.
(18) After the slope reinforcement is completed, arc sliding stability analysis is carried out on the slope, a calculation sketch is shown in fig. 9, the least favorable sliding arc does not pass through the soft soil area reinforced by the dynamic compaction replacement pier 6, the overall stability of the slope is obviously improved, the minimum safety coefficient is 1.359 to 1.35, and the safety stability requirement of the primary permanent slope is met; and monitoring slope engineering, namely monitoring horizontal displacement and vertical displacement of the slope top and slope surface deformation of the slope.
The soft soil foundation filling side slope has high stability after being reinforced, solves the problems of piling and outward transportation of broken stone soil in the excavated area in the field, reduces the treatment cost, does not cause secondary pollution, and simultaneously uses the soil planted by the surface layer tillage of the foundation to configure planting soil so as to avoid the source of outward transportation of soil. The reinforcing method reduces environmental pollution, changes waste into valuable, has high utilization rate, and has better economic and social benefits.
In view of the foregoing, the present invention is not limited to the above-described embodiments, and other embodiments can be easily proposed by those skilled in the art within the scope of the technical teaching of the present invention, but such embodiments are included in the scope of the present invention.
Claims (9)
1. A reinforcing method for soft soil foundation filling side slope is characterized by comprising the following specific steps:
(1) Obtaining physical and mechanical property indexes of a soft soil slope soil layer according to geological investigation, calculating an untreated soft soil slope stability safety coefficient according to a simplified Chinese zodiac method, determining a sliding arc coverage area which cannot meet the slope stability safety coefficient, and determining the depth and the plane processing range of a soft soil reinforcement area; the slope stability safety factor F s The calculation formula of (2) is as follows:
wherein: f (F) s -a soft soil slope stability safety factor;
m θi -calculating coefficients;
l i -ith soil strip bottom slideLength of arc
G i -gravity of the ith soil strip, unit: kN;
G bi -i-th soil strip vertical external force, unit: kN;
c i -i-th soil layer cohesive force, unit: kPa;
-a soft soil slope soil layer internal friction angle;
θ i -the inclination of the bottom slip surface of the ith soil strip;
(2) And (3) carrying out dynamic compaction test on broken stone and filled soil of a slope: selecting a representative field in the soft soil reinforcement area determined in the step (1), performing a slope crushed stone soil filling dynamic compaction test, wherein the area of the test area is not less than 20mx and 20m, and performing a dynamic sounding test on the tamping test area when the tamping of the test area meets the sedimentation requirement to obtain a shear strength index c of the crushed stone soil filling dynamic compaction test area g 、
(3) Dynamic compaction displacement pier test: performing pile forming test in the soft soil reinforcement area determined in the step (1) before construction, determining construction process and parameters of the dynamic compaction replacement piers, wherein the number of test piles is not less than 2, the pile diameter of the dynamic compaction replacement piers is 0.5-1.2 m, the pile depth is at least 1-2 m passing through a sliding arc surface, the pile depth is not more than 20m, and performing dynamic sounding test on the dynamic compaction replacement pier test piles when the tamping of the test piles meets the sedimentation requirement, so as to obtain shear strength index c of the test dynamic compaction replacement pier test piles p Andthe processing depth reaching the dynamic compaction replacement pier, the mass, the hammer length and the drop distance of the hammer required are determined in the dynamic compaction replacement pier test, and the layering filling amount and the tamping times are determined through a process test;
(4) Setting the replacement rate m of the dynamic compaction replacement pier x And m is x The value range is as follows: 5% -30%;and will set m x Value, shear strength index c of dynamic compaction replacement pier determined according to test in step (3) p Andshear strength index c of soil between piles in dynamic compaction displacement pier treatment area determined in geological survey s And->Calculating the shear strength index c of the composite foundation in the dynamic compaction replacement pier treatment area according to the following formula sp And->
c sp ＝m x c p +(1-m x )c s ③
Wherein: c p -dynamic compaction displacement pier cohesive force, unit: kPa;
-dynamic compaction displacement pier internal friction angle, unit: a degree;
c s -cohesive force of soil between piles in the dynamic compaction displacement pier treatment area, unit: kPa;
-friction angle of soil between piles in the dynamic compaction displacement pier treatment area, unit: a degree;
c sp -composite foundation cohesion, unit: kPa;
-composite foundation internal friction angle, unit: a degree;
m x -a set displacement rate of the dynamic compaction displacement pier;
(5) The shear strength index c of the composite foundation calculated in the step (4) is calculated sp Andchecking the stable safety coefficient of the composite foundation in the formulas (1) and (2) in the step (1), and setting the dynamic compaction replacement pier replacement rate m when the stable safety coefficient of the composite foundation meets the slope stable safety coefficient x The value is the replacement rate m of the dynamic compaction replacement pier in the composite foundation;
(6) According to the calculated displacement rate m of the dynamic compaction displacement pier in the step (5), the pile diameter d obtained by pile testing in the step (2), the spacing s of the dynamic compaction displacement pier is calculated according to different pile distribution modes, and a construction design drawing of the dynamic compaction displacement pier is drawn according to the calculation result;
when square piles are distributed: from the following componentsObtain->
When the regular triangle piles are distributed: from the following componentsObtain->
(7) Leveling the site, burying a pore water pressure gauge near a soft soil foundation reinforcing area outside the slope toe, and measuring a pore water pressure reference value of the foundation before the construction of the dynamic compaction replacement pier;
(8) Constructing dynamic compaction replacement piers according to the construction design drawing of the dynamic compaction replacement piers in the step (6) aiming at the soft soil foundation reinforcement area outside the slope toe, constructing the dynamic compaction replacement piers at intervals, and extruding soft soil out of the range of the reinforcement area outside the slope from inside the slope to outside the slope; the construction adopts an impact expansion hammer and a column hammer, wherein the impact end of the impact expansion hammer is conical, and the column hammer is a cylindrical impact hammer; after the construction machine is in place, firstly, tamping a construction point by adopting a punching hammer for multiple times to form a hole with the diameter matched with the diameter of the hammer body, wherein the depth is the design depth of the dynamic compaction replacement pier, then, replacing the dynamic compaction replacement pier column hammer, filling the hole with gravelly soil filler in layers, tamping the gravelly soil filler in the hole by using the column hammer after each filling until the gravelly soil filler reaches a construction operation surface; the dynamic compaction replacement pier filler adopts loose gravelly soil generated in the process of leveling the earthwork of a construction site, gravels with larger particles need to be crushed for the second time, and the particle content of the gravels with the particle size of more than 300mm is not more than 30%;
(9) Monitoring pore water pressure through a pore water pressure gauge buried in advance, fully tamping a field surface layer once after the pore water pressure is dissipated, wherein the tamping energy is 1500-2000 kN.m, and finishing the treatment of the soft soil foundation outside the toe;
(10) The design of a side slope is carried out in a multi-stage manner according to a slope rate method, the width of a graded pavement is controlled to be not less than 2m, the backfill-planning side slope is treated in a layered manner according to the designed height of the side slope, the thickness of each layer of the gravel soil to be treated is determined, and the gravel soil filling and dynamic compaction construction is carried out on the side slope according to the parameters of the step (2) of the slope body gravel soil filling dynamic compaction test; loose gravels are produced in the process of leveling the earthwork of a construction site, the gravels with larger particles need to be crushed for the second time, and the particle content of the gravels with the particle size of more than 300mm is not more than 30%;
(11) After the gravel soil filling dynamic compaction construction of the slope is completed, the backfilled slope is subjected to slope cutting and slope greening, and a slope drainage system is constructed.
2. The method for reinforcing a soft soil foundation filling side slope according to claim 1, wherein: in the step (1), the stability safety coefficient of the untreated soft soil slope is calculated through slope processing software, the sliding arc coverage area which cannot meet the safety coefficient is analyzed by checking the passing position of the least favorable sliding surface, and the depth of the soft soil reinforcement area is determinedA planar processing range; the slope processing software comprises Slide software, positive rock-soil processing software or Nanjing coulomb software; obtaining the dimension of the end face of the side slope and the stratum distribution through geological mapping and reconnaissance, obtaining the physical index and the mechanical index of each soil layer, inputting the reconnaissance parameters into side slope processing software, establishing a side slope two-dimensional model, automatically searching sliding arcs by the software, and dividing the side slope above the sliding arcs to directly obtain the length l of the sliding arc of the ith soil strip bottom of the side slope i Gravity G of ith soil strip i External force G in vertical direction of ith soil strip bi I-th foundation soil layer cohesive force c i Inclination angle theta of ith soil strip bottom sliding surface i And calculating the slope stability coefficient through formulas (1) and (2).
3. The method for reinforcing a soft soil foundation filling side slope according to claim 1, wherein: in the step (3), in the dynamic compaction test of the broken stone filling soil of the slope body, the dynamic compaction energy, the compaction point spacing, the compaction times, the compaction pass number and the effective reinforcement depth parameters are determined by combining the test compaction according to the following table, and the corresponding single-impact compaction energy is selected:
4. the method for reinforcing a soft soil foundation filling side slope according to claim 1, wherein: calculating the amount of soil tillage required for covering and leveling the slope before leveling the site in the step (7), and excavating earth surface soil tillage correspondingly during construction; removing barriers after leveling the field, paying off, defining a control axis, piling the side line of the field and marking, backfilling loose gravel soil on the original ground to form a crust layer on the field surface layer, and facilitating mechanical equipment to enter the field for construction.
5. The method for reinforcing a soft soil foundation filling side slope according to claim 1, wherein: in the step (8), when the punching and expanding hammer is used for punching construction points for a plurality of times, and hole collapse occurs in the punching and expanding hammer hole, the hammer can be lifted to repeatedly impact to the designed depth, and finally a hole with the diameter matched with the diameter of the hammer body is formed; the step (8) of dynamic compaction replacement piers is to divide the spaced pile positions into two groups for construction, after the first group of construction is completed, pore water pressure values of a site are measured by using a pore water pressure gauge which is buried in advance, and after the pore water pressure is dissipated, the construction is performed on the second group of jump positions from the head; the impact expansion hammer is raised to a certain height during construction, then falls freely to impact the hole, and is tamped for multiple times, so that a hole with the diameter of the hammer body and the diameter of the ground is formed, and the hole forming depth is 12-13 m; the average compaction coefficient of the filling material in the pile body of the dynamic compaction replacement pier is not less than 0.98, the number of times of compaction is accumulated to be 1.5-2.0 times of the designed pier length along with the filling of the dynamic compaction replacement pier, and the average compaction amount of the last two strokes is not more than 250mm.
6. The method for reinforcing a soft soil foundation filling side slope according to claim 1, wherein: in the slope backfilling of the step (10), during backfilling of the first grade slope, the gravels are superfilled within 5m of the top line of the filled slope, so that the whole slope can be reinforced by dynamic compaction; marking the position of the tamping point in the first time, measuring the elevation of the field, finishing the tamping of all the tamping points in the first time, filling up the tamping pit by using a bulldozer, and measuring the elevation of the field; after a specified interval time, the whole ramming times are completed according to the steps, and finally, low-energy full ramming is adopted; detecting after each time of tamping, and sequentially completing the second grade slope and the third grade slope filling and dynamic tamping according to the steps after the requirements are met, so that the whole slope body can be reinforced; and (3) when the design elevation from the dynamic compaction surface to the slope top is 40-60 cm, two layers of geogrids are paved at intervals, after each layer of geogrids is paved, a middle sand cushion layer is paved on the surface of each layer of geogrids, then uniform gravel soil is paved, and layering rolling is carried out.
7. The method for reinforcing a soft soil foundation filling side slope according to claim 1, wherein: in the step (11), the slope is cut from top to bottom in layers, and the slope is subjected to greening by adopting a bulldozer and manual trimming, and after finishing the slope cutting, the slope surface of the side slope is greened; the slope greening is specifically realized by digging a slope with a soil coverage value of the ground surface, wherein the coverage thickness is 20 cm-25 cm, sprinkling water for wetting, then paving a three-dimensional net along the slope from top to bottom, and fixing the net pad to the slope from top to bottom by using U-shaped nails and steel nails, wherein the slope top and the slope foot are respectively fixed according to the design requirement; after the three-dimensional net is fully paved and fixed, the soil and fertilizer on the surface of the land are sown from the top of the slope to the bottom of the slope, and the thickness of the soil is sown to cover the net; applying a base fertilizer and a soil conditioner before sowing, sowing grass and irrigating seeds in sections, checking whether the sowing is missed or not at any time, watering in time after sowing, covering an earth work film, and watering in time for maintenance until the survival rate is not lower than 90% when grass is planted into a lawn, and entering into normal maintenance after the lawn is formed; the side slope drainage system is combined with the factory side slope drainage system; and finally, monitoring slope engineering, and monitoring horizontal displacement and vertical displacement of the slope top and slope surface deformation.
8. The method for reinforcing a soft soil foundation filling side slope according to claim 1, wherein: the equipment used for the dynamic compaction replacement piers and the dynamic compaction in the step (2), the step (3), the step (8), the step (9) and the step (10) are the same equipment, and comprise a crane, a cable and a unhooking device, and when the dynamic compaction replacement piers are constructed to pre-form holes, the unhooking device is connected with a punching and expanding hammer; when the filling material in the pier holes is replaced by the dynamic compaction, the unhooking device is connected with the column hammer; when the slope body is rammed dynamically, the unhooking device is connected with the rammer; and setting a dynamic compaction portal frame on the basis of a dynamic compaction machine when constructing the dynamic compaction replacement pier, and stabilizing the crane.
9. The method for reinforcing a soft soil foundation filled side slope according to claim 7, wherein the base fertilizer and the soil conditioner are applied before sowing in the greening of the side slope, the base fertilizer mainly comprises nitrogen fertilizer, phosphate fertilizer and potash fertilizer, the ratio is 15:8:7, and the ratio is 35g/m 2 Administered right and left.
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| CN202210873772.0A CN115288162B (en) | 2022-07-25 | 2022-07-25 | Reinforcing method for soft soil foundation filling side slope |
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