Lateral water seepage prevention and treatment structure for gully high fill engineering

Abstract

The utility model belongs to the technical field of collapsible foundation reinforcement, and relates to a lateral water seepage prevention and treatment structure for gully high fill engineering, which comprises an original slope body, a fill body and a gully, the gully is positioned below the ground level of the original slope body, and the gully penetrates through a plurality of staggered underground soil layers and opposite water-resisting layers below the ground level of the original slope body along the depth direction; a seepage well which is vertically and downwards arranged from the ground is arranged in the valley, the ground position of the seepage well is located at the boundary of the original slope and the fill body and faces one side of the fill body by at least two meters, and the seepage well at least penetrates through one opposite water-resisting layer and further at least penetrates through a seepage horizontal flowing layer or a water-resisting layer which is 10 meters below the bottom of the fill body; the lateral dredging channel is formed through the seepage well, underground seepage water is dredged and drained to a seepage water horizontal flowing layer or a water-resisting layer at the deeper position of the fill body, the fill body is prevented from sinking or deforming, the common lateral seepage problem in the fill project is effectively solved, and the precision and the effect of seepage water prevention and control are improved.

Description

Technical Field

[0001] The utility model belongs to the technical field of collapsible foundation reinforcement and relates to a lateral water seepage prevention and control structure for a gully high filling project. Background Art

[0002] Uneven settlement of fill refers to the phenomenon of different degrees of settlement in different parts of the fill due to the influence of factors such as the physical and mechanical properties of the fill material, the filling method, and geological conditions in the fill project. This uneven settlement may have an adverse effect on the safety and stability of buildings or structures. Although the reasons for the uneven settlement of the fill are complex, lateral seepage from the original ditch in the fill area is one of the main factors. Although the relevant design specifications have clear requirements for the setting of blind ditches at the bottom of the ditch, they do not involve the prevention and control of seepage above the bottom of the ditch. The seepage from the original ditch slope will directly infiltrate the fill, causing a large local settlement of the fill, which will cause serious damage to both the structures on the fill and the stability of the fill itself. With the development of filling engineering practice, even in arid areas with little rainfall, after filling, as time goes by, the accumulation of rainy seasons changes the original hydrogeological environment due to the filling body, which changes the seepage field of the original dry filling valley. Seepage will occur in the half slope of the original valley or at a height where seepage may be enriched, while the seepage above the bottom of the ditch cannot directly seep into the blind ditch set at the bottom of the ditch. Although this type of seepage has a certain seasonality and the flow rate is generally not large, it will continue to occur and is a long-term hidden danger, which has a great impact on the uneven settlement of the filling body. In some projects, the original valley has no groundwater seepage all year round, but during the filling construction process, after two rainy seasons, the lateral fissure water of the original slope seeped from the original half slope, causing the newly completed filling body to collapse, and it had to be re-excavated and replaced on a large scale, causing huge economic losses.

[0003] At present, due to insufficient understanding of the changes in the water environment of the fill valley, there are generally no specific engineering measures for the lateral waterproofing of the valley in the fill area, resulting in seepage problems after construction or even during construction, causing excessive settlement or collapse of the fill body, often resulting in huge economic losses. In arid areas, the original valleys in the fill area are dry all year round, and the valleys only produce surface runoff during rainfall. There is no seepage before the slope is filled. However, with the construction of the fill, the valleys are filled, the hydrogeological environment of the original valleys changes, and lateral seepage will occur in special positions of the valley slope. There are two reasons for this phenomenon. First, as the site grows over time, groundwater accumulates on the slope for a long time after the rainy season. Second, the catchment area of the slope stratum that receives rainwater is much larger than the area near the fill. Large areas receiving rainwater recharge are also the source of lateral seepage on the slope.

[0004] However, in the existing design of high-fill projects, due to the lack of specific drainage facilities for lateral seepage in high fills, or only a few blind ditches are set at the edge of the fill body and the slope body. The design of these blind ditches mainly focuses on the bottom of the ditches, ignoring the prevention and control of lateral seepage. These measures cannot achieve the due effect on discharging the lateral incoming water in the fill, resulting in the lateral incoming water seeping into the interior of the fill body. Although the fill body has undergone compaction operations, it still belongs to the category of disturbed soil and does not have the structural strength of undisturbed soil. The cohesive force between soil particles is low, and seepage will cause the engineering mechanical properties of the filled soil to decline rapidly, resulting in local collapse of the fill body, uneven settlement of the site, and even affecting the overall stability of the fill body, posing a threat to the safety of the upper project.

[0005] Therefore, a device or method is needed to avoid large-area uneven settlement of the fill project caused by seepage in the slope after the completion of the fill to solve the above technical problems. Utility Model Content

[0006] Through a comprehensive analysis of the causes and paths of lateral seepage, the present utility model proposes a lateral seepage prevention and control structure for gully high-fill projects, which conveys the lateral seepage of the slope body to the bottom of the ditch or the strata below the fill body, effectively preventing the fill body from being soaked by water, ensuring the stability and safety of the fill project, and completely solving the anti-seepage problem of the fill body. The seepage position of groundwater is controlled by the strata and structure of the slope body. According to the lithological changes of the slope body, the existence of the aquitard can be determined by using the difference in the permeability coefficient of the rock strata. Combining the analysis of the structural distribution of the slope body, the possible seepage paths of the seepage in the slope body can be analyzed, and the possible seepage positions of the slope body can be accurately judged.

[0007] Based on the strata characteristics and distribution, and geological structure characteristics and distribution of the gully, the present utility model can determine the groundwater seepage field situation. Through the analysis of the groundwater seepage field, an effective seepage prevention and control plan can be designed. The existing seepage prevention and control technologies mainly include two methods: hydrophobic and water-blocking. According to the situation of gully filling, the present utility model selects the hydrophobic prevention and control plan, and adopts the engineering measure of the infiltration well to naturally convey the lateral seepage at the seepage position determined by the analysis of the groundwater flow field to the strata below the fill body, ensuring that the fill body is not harmed by seepage. The present utility model can effectively solve the problem of lateral seepage in high-fill projects, ensure the stability of the fill body, and avoid uneven settlement and engineering safety hazards caused by lateral seepage.

[0008] The technical solution adopted by the utility model to solve the technical problem is as follows: A lateral seepage prevention and control structure for high fill projects in gullies, comprising: the original slope, the filled body, and the gully. The gully is located below the ground plane of the original slope. The gully passes through multiple intersecting underground soil layers and relatively water-resistant layers below the ground plane of the original slope in the depth direction. An infiltration well is arranged vertically downward from the ground in the gully. The ground position of the infiltration well is at least two meters on the side facing the filled body at the boundary line between the original slope and the filled body. The infiltration well penetrates at least one relatively water-resistant layer, and the infiltration well also penetrates at least one horizontal seepage flow layer or water-resistant layer more than 10 meters below the bottom of the filled body;

[0009] There are multiple infiltration wells, which are evenly arranged around the boundary line between the original slope and the filled body in the infiltration well. The distance between adjacent two infiltration wells is not greater than 150 cm, and the diameter of the infiltration well is not less than 40 cm. The infiltration well is filled with 23# - 27# gravel filler; The infiltration well is used to guide the water seeping from the original slope side to the filled body side, forming a guiding channel near the filling boundary line between the original slope and the filled body, and guiding and draining the underground seepage water to the horizontal seepage flow layer or water-resistant layer deeper in the filled body, preventing the filled body from sinking or deforming.

[0010] Preferably, at least two layers are evenly arranged around the boundary line between the original slope and the filled body in the infiltration well, and the infiltration wells between adjacent layers are arranged staggeredly.

[0011] More preferably, the infiltration wells are evenly arranged in two layers around the boundary line between the original slope and the filled body, and the infiltration wells between the inner and outer layers are arranged in an equilateral triangle; that is, the infiltration wells between one layer and two adjacent infiltration wells in the other layer are arranged in an equilateral triangle.

[0012] Preferably, the distance between adjacent two infiltration wells is 120 - 130 cm, and the diameter of the infiltration well is 55 - 65 cm.

[0013] Preferably, the infiltration well is filled with 25# gravel filler.

[0014] Preferably, a blind ditch is arranged at the bottom of the gully, and a cushion layer is covered on the blind ditch. The granular material of the cushion layer is configured with 23# - 27# gravel filler.

[0015] Preferably, the relatively water-resistant layer includes: mudstone, marl.

[0016] The beneficial effects of the utility model are:

[0017] 1. The utility model arranges multiple layers of continuous seepage wells near the boundary between the original slope and the filled body, so that the seepage wells form a lateral diversion channel, diverting the underground seepage water to the deeper horizontal seepage flow layer or impervious layer of the filled body, preventing the filled body from sinking or deforming, effectively solving the common lateral seepage problem in the filling project, and improving the accuracy and effect of seepage prevention.

[0018] 2. The utility model not only solves the problems of local settlement and collapse of the filled body, but also fundamentally guarantees the overall stability and engineering quality of the filled body, and is applicable to various geological conditions and engineering scales.

[0019] 3. The utility model fills the blank in the lateral waterproofing of the filling project in the existing technology, providing new ideas and methods for the technological progress of related fields.

[0020] 4. The utility model effectively avoids the economic losses and environmental impacts caused by lateral seepage in the filling project, improves the sustainable development ability of the project, and meets the requirements of energy conservation, emission reduction and sustainable development in modern engineering construction. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 is a cross-sectional schematic view of a lateral seepage prevention structure for a high-filled gully project of the utility model;

[0022] Figure 2 is a schematic layout diagram of the seepage wells of the utility model.

[0023] Wherein, 1, original slope; 2, filled body; 3, gully; 4, underground soil layer; 5, relative impervious layer; 6, seepage well; 7, horizontal seepage flow layer; 8, blind ditch; 9, cushion layer. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0024] Next, the relevant technologies in the utility model will be clearly and completely described in conjunction with the drawings in the embodiments of the utility model. Obviously, the described embodiments are only a part of the embodiments of the utility model, rather than all the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the protection scope of the utility model.

[0025] Reference Figures 1 - 2 , in the lateral seepage prevention structure for a high-filled gully project of this embodiment, first analyze and determine the seepage position, and then arrange the seepage wells.

[0026] Analyze and determine the seepage position

[0027] 1. Determine the lateral seepage position and scope of the filled body:

[0028] Based on the layered permeability coefficients of the slope strata, the existence of a vertical relatively impermeable layer is determined. Whether there is an impermeable layer is distinguished according to the difference in the order of magnitude of the permeability coefficient of the strata. When the permeability coefficient of the lower strata is less than that of the upper strata by an order of magnitude of 10ˉ2, this layer is considered an impermeable layer. The existence of the impermeable layer can also be judged by lithological differences. Mudstone and argillaceous shale are both impermeable layers, and the top surface of the impermeable layer is the water seepage position. The possible water outlet positions of the slope are determined according to the distribution of faults and fractures in the slope. Tensile faults and vertical fractures are both positions for lateral water inflow.

[0029] 2. Determine the groundwater seepage field situation:

[0030] According to the characteristics of the stratum distribution, including attitude, lithology, permeability coefficient characteristics, and the distribution of faults and fractures, determine the groundwater seepage field situation of the gully after filling, and determine the possible seepage paths. Finally, determine the position of lateral water seepage and the range of water seepage outcropping.

[0031] 3. Judge the situation of the bottom stratum:

[0032] Judge whether there is a relatively impermeable layer in the bottom stratum of the fill body (gully) through the exploration data, and find out whether the groundwater drainage is unobstructed within 10 meters below the bottom. Confirm whether there is an argillaceous interlayer and whether there are rock strata that swell when exposed to water and are prone to weathering.

[0033] Arrange seepage wells

[0034] At the water seepage position of the slope, 2 meters away from the slope in the direction of the slope, arrange two rows of seepage wells from the ground downwards. The two rows of seepage wells are staggered at equal intervals and arranged in a plum blossom pile in an equilateral triangle. The diameter of the seepage well is 60 cm, and the pile spacing is 125 cm. The depth of the seepage well should penetrate the relatively impermeable layer at the bottom of the fill body and not be less than 10 meters below the bottom of the fill body. The seepage well needs to be filled solid with 25# crushed stone filler. The designed width of the seepage well should be more than 2 meters on each side of the water seepage range at the water seepage position of the slope. The setting of the seepage well can effectively guide the lateral water seepage of the slope to the bottom of the gully or the strata below the fill body, ensuring that the fill body is not affected by water seepage.

[0035] Example

[0036] The high-fill project of the sewage treatment plant in a new material industrial park in a certain city is located in the gully on the west side of Zuizi Village in the new area of the city. The width of the gully reaches more than 100 meters. It gradually becomes deeper from the south side of the gully top to the north, and the height difference reaches more than 20 meters within the project area. There are several platforms at the bottom of the original landform of the gully before filling, and the rainfall runoff directly drains northward along the ground. The loess stratum on the west side of the gully slopes eastward. Through field soaking tests, it is found that the seepage water will seep eastward along the paleosol, and there is no seepage phenomenon on the soil cliffs on both sides of the gully before filling. However, the sewage treatment plant project has 14 production monomers arranged at the junction of filling and excavation, and the designed filling thickness ranges from 8 to 20 meters. Through one year of observation, the settlement of the filled body has not yet reached a stable state. The foundation of the filling area of the monomer building adopts pile foundation to prevent uneven settlement, but the pipelines connecting the monomers do not take effective measures at the junction of filling and excavation to solve the problem of differential settlement.

[0037] According to the actual situation analysis of the project, there are potential seepage hazards in the later stage of the filled body, mainly the seepage hazards at the junction of filling and excavation and the deep seepage hazards. The main problem at the junction of filling and excavation is that the settlement of the filling cannot be controlled, resulting in uneven settlement here. Uneven settlement will cause the pipeline to burst and leak. The design and construction units are aware of this hazard but have no effective solution, and the leakage of the pipeline will directly seep into the filled body, causing greater harm. The deep seepage hazard is mainly the seepage at the south slope top and the deep seepage of the original stratum on the west side. At present, neither the design nor the construction takes anti-seepage measures at the bottom or the side of the filled body. Only drainage ditches are designed on the ground, and the ground drainage ditches cannot solve the underground seepage problem.

[0038] To solve the problem of underground seepage in the filled body and prevent seepage water from entering the filled body to ensure the operation safety of the site, a remedial design for the anti-seepage measures of the filled body of the site was carried out according to the content of this utility model. The key point of the design is to solve the problem of the drainage of the downward seepage first. Since there was no drainage blind ditch designed at the bottom of the filled body in the early stage of this project, the drainage depth of the lateral seepage must be considered to be designed below the bottom of the filled body. For the site with a drainage blind ditch and gravel layer designed at the bottom, the design depth of the lateral drainage measures can reach the bottom of the filled body. According to the results of the on-site soaking test, the main layer for the horizontal flow of seepage water is between the third paleosol and the fourth paleosol of the site. Therefore, the design depth of the seepage well must penetrate the third paleosol. The buried depth of the third paleosol of the original site is 25 meters. Considering the change in the stratum depth at the filling position, the actual depth of the seepage well is 45 meters below the existing ground surface.

[0039] As for the layout position of the soakaway wells, they are located at the south end and the west side of the fill body. Based on the principle of completely enclosing the layout section of the soakaway wells without omission, the plum blossom pile layout is adopted. Considering the construction verticality of the soakaway wells and other conditions, they are arranged in 3 rows. Considering the convenience of filling with gravel aggregate, the diameter of the soakaway wells is designed to be 600 mm. The filler of the soakaway wells is constructed according to the grading gravel of No. 25. The best gravel is weather-resistant limestone. The use of mudstone or marlstone aggregate is prohibited, and the use of rock aggregate that is easily weathered when exposed to water is prohibited.

[0040] To sum up, through comprehensive analysis and accurate judgment of the water seepage position and scope of the slope body, the present utility model adopts the prevention and control structure of soakaway well layout, effectively solves the common lateral water seepage problem in the filling project, improves the accuracy and effect of water seepage prevention and control, ensures the quality of the filling project, avoids large-area uneven settlement in the later stage, and brings obvious economic and social benefits; therefore, the present utility model has a wide application prospect.

[0041] It should be emphasized that the above are only the preferred embodiments of the present utility model, and do not impose any form of limitation on the present utility model. Any simple modification, equivalent change and modification made to the above embodiments based on the technical essence of the present utility model still fall within the scope of the technical solution of the present utility model.

Claims

1. A lateral seepage prevention and control structure for high fill projects in gully areas, characterized in that, Including: Original slope body (1), filling body (2), and gully (3). The gully (3) is located below the ground plane of the original slope body (1). The gully (3) penetrates through multiple interlaced underground soil layers (4) and relatively water-resistant layers (5) below the ground plane of the original slope body (1) in the depth direction. A water infiltration well (6) is arranged vertically downward from the ground in the gully (3). The ground position of the water infiltration well (6) is at least two meters on the side towards the filling body (2) at the boundary line between the original slope body (1) and the filling body (2). The water infiltration well (6) penetrates at least one relatively water-resistant layer (5), and the water infiltration well (6) also penetrates at least one water seepage horizontal flow layer (7) or water-resistant layer more than 10 meters below the bottom of the filling body (2). There are multiple water infiltration wells (6). The water infiltration wells (6) are evenly arranged around the boundary line between the original slope body (1) and the filling body (2). The distance between two adjacent water infiltration wells (6) is not greater than 150 cm. The diameter of the water infiltration well (6) is not less than 40 cm. The water infiltration well (6) is filled with gravel fillers of No. 23# to No. 27#. The water infiltration well (6) is used to guide the water seeping from the side of the original slope body (1) to the side of the filling body (2), forming a guiding channel near the filling boundary line between the original slope body (1) and the filling body (2), and guiding and draining the underground seepage water to the water seepage horizontal flow layer (7) or water-resistant layer deeper in the filling body (2) to prevent the filling body (2) from sinking or deforming.

2. The lateral seepage prevention and control structure for a gully high fill project according to claim 1, characterized in that, At least two layers of water infiltration wells (6) are evenly arranged around the boundary line between the original slope body (1) and the filling body (2) in the water infiltration well (6), and the water infiltration wells (6) between adjacent layers are arranged in a staggered manner.

3. The lateral seepage prevention and control structure for a high fill project in a gully according to claim 2, characterized in that, Two layers of water infiltration wells (6) are evenly arranged around the boundary line between the original slope body (1) and the filling body (2) in the water infiltration well (6), and the water infiltration wells (6) between the inner and outer layers are arranged in an equilateral triangle.

4. The lateral seepage prevention and control structure for a gully high-fill project according to claim 1, characterized in that, The distance between two adjacent water infiltration wells (6) is 120 - 130 cm, and the diameter of the water infiltration well (6) is 55 - 65 cm.

5. The lateral seepage prevention and control structure for a gully high-fill project according to claim 1, characterized in that, The water infiltration well (6) is filled with gravel fillers of No. 25#.

6. The lateral seepage prevention and control structure for a gully high-fill project according to claim 1, characterized in that A blind ditch (8) is arranged at the bottom of the gully (3), and a cushion layer (9) is covered on the blind ditch (8). The granular material of the cushion layer (9) is configured with gravel fillers of No. 23# to No. 27#.

7. The lateral seepage prevention and control structure for a gully high fill project according to claim 1, characterized in that, The relatively water-resistant layer (5) includes: mudstone, marl.

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