A quick evaluation technique for evolution of throwing and extruding silt form of soft foundation in a pond

Abstract

The application discloses a technology for evolution and rapid evaluation of a throwing and extruding silt form of a soft foundation of a pond, comprising a throwing and extruding silt construction of the soft foundation of the pond and rapid evaluation of a silt form of a construction site; the rapid evaluation of the silt form of the construction site is achieved by scanning and reconstructing the silt form after the throwing and extruding, obtaining the evolution process and evolution characteristics, and rapidly evaluating the construction effect according to the evolution characteristics. The application introduces laser scanning and terrain reconstruction technology, combines the construction process, and scans the throwing and extruding form and the silt form. Through noise reduction and simplification of the terrain point cloud and other technical treatments, the three-dimensional form reconstruction of the throwing and extruding body and the silt body is finally realized, the evolution process is realized, and the evolution characteristic analysis is realized. The implementation of the technology can significantly improve the accuracy of the engineering quantity measurement, the settlement quantity of the roadbed and other parameters.

Description

Technical Field

[0001] This invention belongs to the field of water conservancy and municipal engineering technology, specifically relating to a technology for the morphological evolution and rapid evaluation of soft soil foundation dumping and siltation in ponds and lakes. Background Technology

[0002] Rock dumping and silt squeezing is a common method for treating soft soil subgrades. It mainly involves dumping a certain amount of crushed stones from the middle of the subgrade to both sides to squeeze the silt out of the engineering area, thereby replacing the silt and improving the bearing capacity of the subgrade [Xu Haibo. Research status of rock dumping and silt squeezing construction technology [J]. Shanxi Architecture, 2019(10):2]. It is generally used when the silt layer is shallow (not greater than 3.0m). When the silt thickness is large, it should be used with caution. According to the relevant provisions of the Highway Subgrade Construction Technical Specification [China Communications First Highway Engineering Bureau Co., Ltd. Highway Subgrade Construction Technical Specification JTG (JTG 10-2006). Released on 2006-09-31 and implemented on 2007-01-01 [M]. People's Communications Press, 2007], (1) the thickness or diameter of the selected stones should not be less than 300mm. (2) Depending on the flatness of the strata and the state of the silt, the construction method should be selected, such as dumping stones from the centerline to both sides or filling from the high slope foot to the low slope foot. According to the relevant provisions of the construction specifications for dike engineering in the water conservancy industry [SL 260-2014, Construction Specifications for Dike Engineering [S]], (1) Hard stones with a diameter of not less than 30cm should be used for riprap extrusion. (2) When the riprap is exposed on the soil surface, smaller stones should be used to fill and compact it, and then a filter layer should be laid on top and the dike body should be filled. However, the above specifications only specify the particle size, hardness and order of riprap, and do not specify the quality control standards for riprap extrusion. Wang Dongsheng [Wang Dongsheng. Application and analysis of riprap extrusion method for soft foundation treatment [J]. Foundation Treatment, 2003, 14(1):9] pointed out through engineering examples that the content of large-diameter riprap in the filling material should be more than 50%, and clay and sand should be used as little as possible or not at all. Alternatively, traditional materials can be replaced with foamed concrete [Cheng Qiang. Replacement technology of foamed concrete under soft soil conditions in highways [J]. Transportation World, 2022(15):130-132], to improve its application level in replacement of highways and other places, and effectively reduce the self-weight of the foundation and settlement problems. Or, crushed stone can be used as filler to improve the strength and stability of the foundation [Hu Yanchao. Analysis of key points of construction technology for replacing soft soil with crushed stone soil in highways [J]. China Standardization, 2017(04):168-169], while improving the replacement method, such as the cushion layer method. The cushion layer method involves excavating the weak soil layer within a certain range below the foundation bottom, and then filling it in layers with sand, crushed stone, plain soil, etc. with greater strength, and compacting (or vibrating) it to the required density. In addition, methods that improve upon the existing soft soil foundation without excavation include, for example, high-pressure jet grouting [Chen Chunsheng. Research on High-Pressure Jet Grouting Technology and Its Application [D]. Hohai University, 2007][Sun Linghui, Lu Lisha. Defects and Countermeasures of High-Pressure Jet Grouting Technology [J]. Northeast Geotechnical Engineering Company, Ministry of Water Resources, 2012]. High-pressure equipment is used to create a high-pressure jet of grout exceeding 20 MPa, which is then ejected from a nozzle to impact and damage the soil.After the grout solidifies, it forms a solidified body that together with the soil between the piles constitutes a composite foundation, thereby improving the bearing capacity of the foundation, reducing the deformation of the foundation, and achieving the purpose of foundation reinforcement. Summary of the Invention

[0003] It is clear from the above research findings that most studies focus on construction techniques, while less attention is paid to the evolution of siltation morphology and the determination of siltation volume after rock placement. However, the evolution of morphology and siltation volume is not only important for evaluating the effectiveness of rock placement, but also for developing related theories on rock placement and silt removal.

[0004] In view of this, the present invention provides a technology for the morphological evolution and rapid evaluation of soft soil foundation dumping and siltation in ponds and lakes.

[0005] The objective of this invention is achieved through the following means: A technique for analyzing the morphological evolution of siltation after dumping into soft soil in ponds and lakes involves scanning and reconstructing the siltation morphology following dumping to obtain its evolution process and characteristics. The acquisition of these siltation morphological evolution characteristics includes the following steps: a. Clean up the construction site and use a laser scanner to scan the area where silt was dumped and squeezed out, and save the initial topographic data; b. After casting, use a laser scanner to scan the shape of the cast object and the siltation pattern, and save the terrain data; c. Use machinery to compact the material, and then scan the shape of the compacted material and the siltation pattern to save the terrain data. d. The above data is processed sequentially according to the construction process. The entire process includes data stitching, noise reduction, and simplification. Three-dimensional reconstruction is then performed on the processed data to obtain the evolution process and characteristics of the siltation morphology.

[0006] The above-mentioned technology for the evolution of siltation morphology in soft soil foundation dumping in ponds and lakes involves obtaining the three-dimensional morphological features of the dumped and discharged bodies. Step a involves setting up a scanning device, leveling and correcting it, setting parameters, scanning the target area, and saving the data. Steps b and c are repeated according to the construction sequence. The device coordinates should be kept consistent during each scan. If they are inconsistent, the data needs to be processed later. Step d is based on the differential geometry theory of discrete surfaces and uses a local nth-order surface parameter algorithm to fit the surface, finally obtaining the reconstructed three-dimensional morphological features of the dumped and discharged bodies.

[0007] The above-mentioned technology for the evolution of the morphology of soft soil foundation dumping and siltation in ponds and lakes involves obtaining the three-dimensional morphological evolution process of the dumped body and the silted body. The specific steps are as follows: Based on the three-dimensional morphological features obtained above, according to the construction process, the three-dimensional morphologies after reconstruction are overlaid in the same coordinate system to obtain the morphological evolution features.

[0008] The aforementioned pond and lake soft soil foundation dumping and siltation morphology evolution technology, characterized by the three-dimensional morphological evolution features of the dumped body and the silt-discharging body, is as follows: a. Localized bulging deformation: After the stone is thrown, it sinks and some silt is squeezed out, but it shows the characteristics of localized siltation. The amount of siltation is related to the thrown stone and is generally small. The bulging shape is slightly wider and slightly lower in height. b. Heaving deformation; Under loading, the heaving shape is continuous, and the amount of siltation is significantly increased compared to the throwing stage, accompanied by displacement. From the characteristics of the heaving shape, the heaving is slightly wider and higher; c. Rise and displacement deformation: After the second pressurization, the ridge shape is still continuous, and the amount of siltation in the first loading stage is significantly reduced, and the displacement change is also relatively reduced. The width and height of the ridge shape have increased, but the trend is weaker, between the throwing and the first loading. The width-to-height ratio is similar to that in the throwing stage, but slightly greater than that in the throwing stage.

[0009] A rapid evaluation technology for the morphology of dumping and squeezing silt in soft soil foundations in ponds and lakes is proposed. Based on any of the aforementioned characteristics of dumping and squeezing silt in soft soil foundations in ponds and lakes, the evolution of the width-to-height ratio of the dumping and squeezing silt body in ponds and lakes generally shows an inverted "V" shaped trend. This evolution characteristic is used to quickly evaluate the dumping and squeezing effect at the construction site, so as to provide feedback and guide the optimization of construction technology.

[0010] Compared with the prior art, the present invention has the following technical effects: By introducing laser scanning and terrain reconstruction technologies, combined with the construction process, the dumping and siltation patterns are scanned. Through noise reduction and simplification techniques on the terrain point cloud, the three-dimensional morphology of the dumped and silted bodies is reconstructed, and the evolution process and evolution characteristics are analyzed. This technology can significantly improve the accuracy of engineering quantity measurement and parameters such as roadbed settlement.

[0011] At the same time, this technology can also be used to obtain the evolution process of throwing and siltation patterns based on the construction progress sequence, providing new technical support for the optimization of construction technology and even the development of throwing theory. Attached Figure Description

[0012] Figure 1 This is the original topographic map of the dumping and siltation area in the initial auxiliary state of this invention.

[0013] Figure 2 This is the original point cloud map of the throwing and silt-squeezing area in the initial auxiliary state of this invention.

[0014] Figure 3 This is a diagram showing the morphology of the silt-squeezing process after the present invention has been completed.

[0015] Figure 4 This is a diagram showing the morphological evolution of the invention from its initial stage to its throwing process.

[0016] Figure 5 This is a diagram showing the morphological evolution of the process from laying to static pressure according to the present invention.

[0017] Figure 6 This is a diagram showing the shape evolution after secondary static pressure according to the present invention.

[0018] Figure 7 This is a flowchart of the construction process of the present invention. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions in the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this application are within the scope of protection of this invention.

[0020] A technology for the evolution and rapid evaluation of siltation morphology after dumping into soft soil foundations in ponds and lakes is proposed. This technology involves scanning and reconstructing the siltation morphology after dumping to obtain its evolution process and characteristics, and then rapidly evaluating the construction effect based on these characteristics.

[0021] The specific steps and characteristics of the morphological evolution of soft soil foundation dumping and siltation in Tanghu are as follows: I. Implementation Process of Construction Preparation Phase (1) Optimization of gradation of thrown stones The main raw material for rockfill silt removal is boulders, and the quality of the raw materials directly affects the quality of the boulders silt removal process. The quality requirements for raw materials are as follows: boulders, especially hard boulders, must meet certain strength requirements; the stone should be uniform in quality, not easily weathered, free of cracks, peeling, or severely corroded. Severely corroded stones are not permitted. This invention proposes a new method for optimizing the proportion of boulders to replace the traditional soil mechanics proportions, which is easily identifiable and easy to operate. Specifically, the boulders are designed for placement according to three grades: hard boulders, coarse aggregate, and fine aggregate, with the gradation increasing sequentially according to the placement order. For ease of discussion, the maximum particle size ratio of each group represents the particle size distribution characteristics of this working condition, as follows: Hard stones, 3-5mm in size, with the largest particle size in this grade being... D max =5mm; Coarse aggregate 1~2mm, the maximum particle size in this grade is D mid =2mm; Fine aggregate 0.1~1mm, the maximum particle size in this grade is D min =1mm; Therefore, taking fine aggregate as the benchmark, the ratio of the maximum particle size of hard stones to that of fine aggregate is: D max : D min =5:1, the ratio of the maximum particle size of coarse aggregate to fine aggregate is 5:1. D mid : D min =2:1; The gradation ratio of the parabolic blocks in this group is 5:2:1. The design particle size distribution relationship is shown in Table 1 below.

[0022] Table 1. Relationship of Stone Particle Size Distribution In the above table, D The sum of particle size distribution values ​​is a dimensionless parameter, expressed by the following formula. (1) It should be noted that this gradation ratio does not involve the amount of material thrown; the amount of material thrown needs to be discussed on a case-by-case basis.

[0023] (2) Optimization and preparation of throwing construction procedures The present invention describes a method for constructing riprap and compaction in soft soil foundations in ponds and lakes, which is divided into three stages: construction preparation, construction organization, and final acceptance. The specific construction content and process for each stage are shown in the diagram below, and will not be elaborated further. It is important to emphasize that when riprap is being placed, the principle of prioritizing hard stones, followed by coarse stones, and finally fine stones should be strictly followed.

[0024] (3) Construction preparation a. Remove weeds, dead branches, etc. from the surface around the dumping and silt-draining area; b. Throwing and compacting the silt-draining area; (4) Original terrain scanning and reconstruction a. Before throwing, use a laser scanner to scan the throwing and silt-squeezing area and save the data of the initial auxiliary equipment status; b. Scan the silt-squeezing area after shoveling and compaction, and save the data after shoveling and compaction; c. The data from the initial auxiliary state and the data after throwing and squeezing are spliced, denoised and simplified to obtain preprocessed data. The preprocessed data is then used to reconstruct surfaces from points.

[0025] This invention relates to a three-dimensional scanning and reconstruction technology for the morphology of rock dumping and siltation in soft soil foundations of ponds and lakes. In step c of the rock dumping and siltation morphology scanning and reconstruction, the initial auxiliary state data and the data after rock dumping and siltation are tilted and corrected, and then the surface is reconstructed.

[0026] The present invention relates to a technology for the evolution of siltation morphology in soft soil foundations in ponds and lakes. The surface reconstruction is a three-dimensional surface reconstruction. The specific steps are as follows: Based on the above data preprocessing, based on the differential geometry theory of discrete surfaces, a local nth-order surface parameter algorithm is used to fit the surface, and finally the reconstructed siltation morphology characteristics can be obtained.

[0027] The project area was scanned, stored, preprocessed, denoised, simplified, and corrected according to the terrain process. Then, other auxiliary calculation tools, such as Southern CASS 7.0, Matlab, and Surfer, were used to reconstruct the terrain surface. The reconstructed projectile morphology characteristics are as follows: Figure 3 As shown.

[0028] II. Specific Implementation Process of Construction Organization (1) Throwing stones Different gradations of rubble were transported by dump trucks to the designated location at the rubble dumping and silt squeezing construction site. During the stockpiling process, in order to ensure that the mud content of the rubble met the design requirements (mud content less than 10%), preliminary washing was carried out to avoid secondary pollution; secondly, the rubble was strictly separated and stockpiled to avoid mixing of gradations.

[0029] The optimized riprap gradation is applied sequentially to the designated area. First, hard riprap (60-100cm) is applied. Layered application is used, with each layer not exceeding 0.6m in thickness, ideally 0.3-0.6m. The application proceeds from the center outwards, then to the left and right sides, to force the silt outwards. Using the roadbed centerline as a reference, stones are applied symmetrically to both sides and forwards in an approximate isosceles trapezoidal shape, further compressing the silt to the lateral areas.

[0030] (2) Throwing and rolling After the hard boulders are placed, compaction is carried out using a 22t heavy roller to accelerate the settlement and silt removal of the boulders and the formation of the roadbed. When compacting the roadbed, the middle section is compacted first, then the outer sections, and finally the middle section again. At the same time, care should be taken to control the overlap distance within the design requirements to ensure that the compacted roadbed meets construction requirements. Compaction is carried out at the designed speed and number of passes, including two static passes and four to six vibratory passes, until the surface is compacted. During the boulders placement and silt removal compaction process, temporary monitoring piles are used to test the settlement stability. The settlement difference between two consecutive compaction passes should be within 5mm, and the standard deviation should be within 3mm to control the compaction quality.

[0031] After the above processes are completed, coarse aggregate (20~40cm), fine aggregate (1~10cm) and filler are thrown and compacted. The entire process is the same as that for hard stone blocks.

[0032] (3) Terrain scanning and reconstruction The operation process is the same as the above-mentioned construction preparation stage.

[0033] III. Specific Implementation Process of Compaction and Leveling Construction (1) Rolling and leveling After the fine aggregate (1~10cm) is thrown and compacted, a final layer of even finer aggregate (0~3cm), i.e., filler, is thrown in, and then bulldozed and compacted to meet the design parameters, thereby filling the gaps and improving the overall quality of the project.

[0034] (2) Terrain scanning and reconstruction The same operational procedures as those for construction preparation and boulder throwing are applied.

[0035] IV. The evolutionary characteristics of siltation morphology are as follows: a. Localized bulging deformation: After the stones are placed, they sink and some silt is squeezed out, but this exhibits characteristics of localized siltation. The amount of siltation is related to the factors affecting the placement of the stones, but is generally small. The bulges are slightly wider and slightly lower in height. Figure 4 As shown.

[0036] b. Heaving deformation; Under loading, the heaving shape is continuous, and the amount of siltation is significantly increased compared to the throwing stage, accompanied by displacement. From the characteristics of the heaving shape, the heaving is slightly wider and its height increases, such as... Figure 5 As shown.

[0037] c. Heave and Displacement Deformation: After the second pressurization, the heave morphology remained continuous, and the amount of siltation during the first loading stage was significantly reduced, as was the displacement change. The width and height of the heave morphology increased, but the trend was weaker, falling between the throwing stage and the first loading stage. The width-to-height ratio was similar to that of the throwing stage, but slightly greater. Figure 6 As shown.

[0038] A method for rapid evaluation of the siltation morphology of soft soil foundation dumping in ponds and lakes is as follows: The siltation effect at the construction site is rapidly evaluated by utilizing the evolution characteristics of siltation morphology, so as to provide feedback and guide the optimization of construction technology.

[0039] The evolutionary characteristics of siltation morphology are as follows: a. Localized bulging deformation: After the stones are placed, they sink and some silt is squeezed out, but this exhibits characteristics of localized siltation. The amount of siltation is related to the factors affecting the placement of the stones, but is generally small. The bulges are slightly wider and slightly lower in height. Figure 4 As shown.

[0040] b. Heaving deformation; Under loading, the heaving shape is continuous, and the amount of siltation is significantly increased compared to the throwing stage, accompanied by displacement. From the characteristics of the heaving shape, the heaving is slightly wider and its height increases, such as... Figure 5 As shown.

[0041] c. Heave and Displacement Deformation: After the second pressurization, the heave morphology remained continuous, and the amount of siltation during the first loading stage was significantly reduced, as was the displacement change. The width and height of the heave morphology increased, but the trend was weaker, falling between the throwing stage and the first loading stage. The width-to-height ratio was similar to that of the throwing stage, but slightly greater. Figure 6 As shown.

[0042] In summary, the width-to-height ratio generally exhibits an inverted "V" shaped evolution trend in other stages. This characteristic can be used to conduct a preliminary evaluation of the silt-draining effect at the construction site.

[0043] The above description is only a preferred embodiment of the present invention. It should be noted that those skilled in the art can make several changes and improvements without departing from the overall concept of the present invention. These changes should also be considered within the scope of protection of the present invention, and will not affect the effectiveness of the implementation of the present invention or the practicality of the patent.

Claims

1. A rapid evaluation method for the morphological evolution of soft soil foundation excavation and siltation in ponds and lakes, characterized in that: By scanning and reconstructing the siltation morphology after casting, its evolution process and characteristics are obtained. The steps to obtain the siltation morphology evolution characteristics are as follows: a. Clean up the construction site and use a laser scanner to scan the area where silt was dumped and squeezed out, and save the initial topographic data; b. After casting, use a laser scanner to scan the shape of the cast object and the siltation pattern, and save the terrain data; c. Use machinery to compact the material, and then scan the shape of the compacted material and the siltation pattern to save the terrain data. d. The above data are processed sequentially according to the construction process. The entire processing includes data splicing, noise reduction, and simplification. The processed data is then reconstructed in three dimensions to obtain the three-dimensional morphological evolution process and characteristics of the thrown body and the silted body. e. By utilizing the three-dimensional morphological evolution process and three-dimensional shape evolution characteristics of the dumped and extruded silt bodies, it is found that the overall evolution of the width-to-height ratio of the dumped and extruded silt bodies in pond and lake soft soil foundations shows an inverted "V" shaped trend. This evolution characteristic is used to quickly evaluate the dumping and extrusion effect at the construction site, so as to provide feedback and guide the optimization of construction technology.

2. The rapid evaluation method for the morphological evolution of soft soil foundation dumping and siltation in ponds and lakes according to claim 1, characterized in that: In step a, the scanning equipment is set up, leveled, calibrated, and parameter set is completed, and the target area is scanned and the data is saved. Steps b and c are repeated according to the construction procedure. The equipment coordinates should be kept consistent each time the scanning is performed. If they are inconsistent, the data needs to be processed later. Step d is based on the differential geometry theory of discrete surfaces. The local nth degree surface parameter algorithm is used to fit the surface, and finally the three-dimensional morphological features of the reconstructed throwing body and the silt discharge body are obtained.

3. The rapid evaluation method for the morphological evolution of soft soil foundation dumping and siltation in ponds and lakes according to claim 2, characterized in that: Based on the obtained three-dimensional morphological features, the morphological evolution features are obtained by overlaying and mapping each reconstructed three-dimensional morphology in the same coordinate system according to the construction process.

4. The rapid evaluation method for the morphological evolution of soft soil foundation dumping and siltation in ponds and lakes according to claim 1, characterized in that: The three-dimensional morphological evolution characteristics of the thrown body and the silt-out body are as follows: d.

1. Local bulging deformation: After the stone is thrown, the stone sinks and some silt is squeezed out, but it shows the characteristics of local silt out. The amount of silt out is related to the thrown body and is relatively small overall. The bulging shape is slightly wider and slightly lower in height. d.

2. Heaving deformation; Under the action of loading, the heaving shape is continuous, and the amount of siltation is significantly increased compared with the throwing stage, accompanied by displacement. From the characteristics of the heaving shape, the heaving shape is slightly wider and the height is increased. d.

3. Rise and displacement deformation: After the second pressurization, the ridge shape is still continuous, and the amount of siltation in the first loading stage is significantly reduced, and the displacement change is also relatively reduced. The width and height of the ridge shape have increased, but the trend is weaker, between the throwing and the first loading. The width-to-height ratio is similar to that in the throwing stage, but slightly greater than that in the throwing stage.

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