Ultra-soft sludge drainage-layer-free ultra-high reinforced body preloading treatment structure and method

Abstract

The invention provides an ultra-soft sludge drainage-layer-free ultra-high reinforced body preloading treatment structure and method. The treatment structure comprises a reinforced body working cushion layer, a water separation and drainage reinforced body structure and an ultrahigh reinforced body stacking structure layer. The reinforced body working cushion layer comprises machine-made sand and an A-type geocell, the water insulation and drainage reinforced body structure comprises non-woven geotextile, a seepage insulation film and multiple layers of composite drainage grids, the composite drainage grids are adopted to replace a medium-coarse sand drainage layer, a vertical plastic drainage plate is directly connected with the middle layer of composite drainage grids, and the vertical plastic drainage plate is directly connected with the middle layer of composite drainage grids. The ultrahigh reinforced body stacking structure layer comprises non-woven geotextile, construction waste, B-type geocells and mineral powder. During design and calculation, the newly filled soil below the water insulation and drainage reinforced body structure is considered as an additional stress load, meanwhile, the load diffusion effect of the reinforced body is considered, and the method is good in foundation treatment effect, capable of reducing the sand consumption and saving the manufacturing cost, clear in calculation principle and method, convenient to design and apply in engineering, and very wide in engineering application prospect.

Description

Technical Field

[0001] The invention belongs to the technical field of ultra-soft mud foundation treatment, and in particular relates to an ultra-high reinforced body loading pre-compression treatment structure and method suitable for thick ultra-soft mud. Background Art

[0002] Ultra-soft silt has low bearing capacity, high compressibility, high water content, and low strength, which makes it difficult to meet engineering requirements. Therefore, when encountering such soil in engineering construction, foundation treatment must be carried out. Due to the low bearing capacity of the top surface of the silt, it is usually necessary to set up a construction surface cushion to ensure the smooth operation of subsequent construction machinery. Ultra-soft silt is often treated by preloading. The common construction process of preloading reinforcement treatment of ultra-soft silt is: laying a layer of woven cloth → laying a construction surface cushion of fine sand or sea sand → laying a vertical plastic drainage board → laying a medium-coarse sand horizontal drainage layer → filling mountain stones → preloading and drainage → strong tamping; the head of the plastic drainage board is buried in the medium-coarse sand cushion layer, and the water in the silt enters the horizontal medium-coarse sand drainage layer through the vertical plastic drainage board channel under the action of the overlying load, and then drains away. Due to the extremely tight supply of sand at home and abroad, the cost of fine sand, sea sand and medium-coarse sand is extremely high, and the supply of sand is tight. The existing construction method of preloading and reinforcing ultra-soft silt leads to high cost and long construction period for foundation treatment of similar projects. Moreover, the strength bearing capacity of the construction surface cushion layer of pure fine sand or sea sand is limited, and the subsequent construction machinery operation settlement and deformation are large. It is urgent to find a construction surface cushion layer with high bearing capacity.

[0003] In addition, in the existing large-area preloading settlement calculation process, the vertical additional stress is usually simply equivalent to the weight of the preloading material * the height of the preloading material. There is still controversy as to whether the recent fill below the drainage system should be regarded as an additional stress load. In addition, the vertical additional stress calculation usually does not consider the load diffusion effect of the reinforced body, resulting in a large difference in the vertical additional stress calculation results, which in turn leads to a large difference between the settlement calculation results and the measured results. Summary of the invention

[0004] In order to quickly and effectively treat super-soft silt, the present invention provides a super-soft silt drainage layer-free ultra-high reinforced body loading preloading treatment structure and method. The present invention arranges a construction surface reinforced body structure, a drainage reinforced body structure, and a super-high reinforced body loading structure, and adopts a three-layer composite drainage grid to replace the medium-coarse sand drainage layer, and connects the plastic drainage board to the middle layer of composite drainage grid. In the design and calculation, the recent fill below the drainage system is considered as an additional stress load, and the load diffusion effect of the reinforced body is considered at the same time. This method has good foundation treatment effect, reduces sand consumption, saves construction cost, has clear calculation principles and methods, and is convenient for design and engineering application.

[0005] In order to achieve the above technical purpose, the present invention provides an ultra-soft sludge non-drainage layer ultra-high reinforced body loading pre-compression treatment structure, the treatment structure comprises a reinforced body working cushion layer, a drainage reinforced body structure and an ultra-high reinforced body loading structure layer;

[0006] The reinforced working cushion layer includes a woven cloth layer laid on the top surface of the ultra-soft silt layer and a reinforced composite layer located above the woven cloth layer, wherein the reinforced composite layer is composited by an A-type geocell and a machine-made sand blowing fill layer;

[0007] The drainage reinforcement structure includes a seepage-proof membrane, a multi-layer horizontal composite drainage net and a plurality of vertical drainage boards. The vertical drainage board is inserted into the ultra-soft silt layer, and its bottom end is embedded in the clay layer at the bottom of the ultra-soft silt layer. The seepage-proof membrane is laid on the top surface of the reinforced body working cushion layer, and the multi-layer horizontal composite drainage net is laid in sequence above the seepage-proof membrane. The top of the vertical drainage board is higher than the seepage-proof membrane and is connected to the reinforcement material of the middle layer horizontal composite drainage net.

[0008] The ultra-high reinforced loading structure layer includes a first non-woven fabric layer laid on the top surface of the drainage reinforced structure layer, a composite landfill layer of construction waste and geocells stacked on the first non-woven fabric layer, a second non-woven fabric layer laid on the top surface of the composite landfill layer, and a mineral powder backfill layer stacked above the second non-woven fabric layer; the composite landfill layer is composed of a construction waste impact rolling layer and a type B geocell.

[0009] The preferred technical solution of the present invention is: the woven fabric layer is made of 150g / m 2 The reinforced composite layer includes a bottom A-type geocell, a middle A-type geocell and a machine-made sand blowing fill layer with a thickness of 1 to 2 m. The bottom A-type geocell is arranged on the top surface of the woven cloth layer, and the middle A-type geocell is located in the middle of the machine-made sand blowing fill layer.

[0010] The preferred technical solution of the present invention is as follows: the vertical drainage board is constructed by a board inserting machine to form a vertical plastic drainage board, the bottom of the plastic drainage board enters the clay layer by no less than 1.0m, the vertical drainage boards are spaced 0.8 to 1.0m apart, and are arranged in a square shape; the seepage-proof membrane adopts a HDPE seepage-proof membrane, and its thickness is not less than 1.5mm; the horizontal composite drainage net is provided with three layers, and the vertical drainage board is connected to the reinforcement material of the middle layer horizontal composite drainage net.

[0011] The preferred technical solution of the present invention is as follows: the height of the composite landfill layer is 3 to 6 m, the bottom and top layers are both construction waste impact compaction layers, and a plurality of B-type geocells are arranged in the middle. Each construction waste impact compaction layer is a backfill compaction layer with a thickness of 0.8 to 1.2 m formed by backfilling construction waste with a particle size not greater than 20 cm and then impact compacting it. The construction waste is a filler with a particle size not greater than 20 cm formed by crushing granular bricks and cement concrete blocks; the height of the mineral powder backfill layer is 1 to 3 m, and the height of the mineral powder backfill layer is less than the height of the composite landfill layer.

[0012] A more preferred technical solution of the present invention: the A-type geocell in the reinforced composite layer adopts a polyester tensile geocell, and the tensile strength limit value is not less than 180kN / m.

[0013] The preferred technical solution of the present invention is that the density of the HDPE barrier membrane is not less than 0.95 g / cm 3 , the roughness height is not less than 0.3mm, the yield strength is not less than 25N / mm; the horizontal composite drainage net adopts a 6.3mm thick composite geotextile drainage grid, and the longitudinal water conductivity is not less than 1*10 -3 m 2 / s, longitudinal tensile strength not less than 18kN / m, unit area mass not less than 200g / m 2 .

[0014] The preferred technical solution of the present invention is that the first non-woven fabric layer and the second non-woven fabric layer are both 300g / m 2 The non-woven geotextile, the B-type geocell adopts a polyethylene extruded geocell, and the tensile strength limit value is not less than 30kN / m.

[0015] In order to achieve the above technical objectives, the present invention also provides a method for preloading treatment of ultra-soft sludge drainage-free layer ultra-high reinforced body, the method adopts the above ultra-soft sludge drainage-free layer ultra-high reinforced body preloading treatment structure for preloading, and specifically comprises the following steps:

[0016] S1. Set the composite filling thickness of construction waste and geocell in the super-high reinforced body loading structure layer to h2 and the mineral powder loading height to h1, where h1 is 1 to 3m, h2 is 3 to 6m and h 2＞ h1; combined with the current ground elevation H of the foundation to be treated d , Foundation treatment delivery surface elevation H s The settlement of the super-soft silt soil layer during the construction period S is calculated based on the requirements and the thickness of the reinforced working cushion h3. t ; By adjusting the set values ​​h1, h2, the design height h1, h2 and the calculated S t The value meets the following requirements:

[0017] h1+h2+h3>H s -H d

[0018] H d +h1+h2+h3-S t -h1=H s

[0019] In the formula, S t Settlement of super-soft silt soil layer during construction period;

[0020] The design values ​​h1 and h2 that meet the above requirements are used as the height of the mineral powder pile and the thickness of the composite filling of construction waste and geocell in the actual pile;

[0021] S2. Determine the foundation treatment area, determine the construction zones, and start construction;

[0022] S3. A foam board is set up on the top surface of the ultra-soft silt layer, and a layer of woven cloth is laid, and then a layer of type A geocell is laid on the woven cloth. The connection of the type A geocell is spliced. After the laying is completed, 50cm to 60cm of machine-made sand is blown in, and then another layer of type A geocell is laid. The connection of the type A geocell is spliced, and 50cm to 60cm of machine-made sand is blown in again;

[0023] S4. Lay a layer of seepage-proof membrane with a thickness of not less than 1.5 mm, and then use a plate inserter to construct a plastic vertical drainage board. The bottom of the plastic drainage board penetrates the ultra-soft silt layer and enters the clay layer by not less than 1.0 m. The spacing between the vertical drainage boards is 0.8 to 1.0 m, and the board head is higher than the seepage-proof membrane; lay a multi-layer composite geotextile drainage grid, tie and connect the board head of the vertical drainage board with the composite geotextile drainage grid of the middle layer, and then use a seepage-proof membrane to wrap the four sides of the vertical drainage board, and seal it with the seepage-proof membrane on the top of the machine-made sand to ensure the water-proof effect;

[0024] S5. Lay a layer of non-woven geotextile on the top surface of the top composite geodrainage grid, and start backfilling construction waste. First, backfill 0.8 to 1 m of construction waste, impact and roll, lay a layer of type B geocell, then backfill 0.8 to 1 m of construction waste, impact and roll, and then lay a layer of type B geocell. Repeat the above steps until the composite filling thickness of construction waste and geocell reaches the composite filling thickness h2 of construction waste and geocell determined in step S1;

[0025] S6. Lay another layer of non-woven geotextile on the top surface of the topmost construction waste landfill compaction layer, and start to fill the mineral powder. After the mineral powder filling height reaches the mineral powder loading height h1 determined in step S1, preloading is performed.

[0026] The preferred technical solution of the present invention is: the settlement amount S of the ultra-soft silt layer during the construction period in step S1 is tThe calculation process is as follows:

[0027] (1) Under the action of the overlying load, the reinforced body in the reinforced working cushion layer of the construction surface is bent and deformed, compressive stress is generated in the upper part of the reinforced body, shear force is generated in the filler of the geocell, and tensile force is generated in the lower geocell. The load of the horizontal composite drainage network is ignored in the calculation process; the vertical shear force τ generated by the reinforced working cushion layer is:

[0028]

[0029] Where: τ—vertical shear force generated by the reinforced body working cushion, unit kPa;

[0030] —Internal friction angle of the reinforced working cushion filler, unit: °; for machine-made sand, 25°;

[0031] K—passive earth pressure coefficient,

[0032] σ v —Self-weight load of the reinforced working cushion;

[0033] The calculation process of the self-weight load of the reinforced working cushion layer is as follows:

[0034] σ v =r3z

[0035] r3—weight of the reinforced body working cushion filler, unit: kN / m 3 ;

[0036] z—the vertical elevation of the reinforced body working cushion from the top downward; the elevation of the top surface of the reinforced body working cushion is 0, and the elevation of the bottom surface of the reinforced body working cushion is h3;

[0037] The vertical shear force τ′ of the reinforced body working cushion filler is taken as the average value of the top and bottom surfaces, and the top surface height z is taken as 0, that is, the self-weight load σ of the top surface of the reinforced body working cushion v顶 = 0, vertical shear force τ on the top surface of the reinforced body working cushion 顶 =0, then:

[0038] τ′=1 / 2(τ 顶 +τ 底 )=1 / 2τ 底

[0039]

[0040] σ v底 =r3 h3

[0041] Based on this calculation:

[0042]

[0043] Where: r3—weight of the reinforced body working cushion filler, unit: kN / m 3；

[0044] h3—thickness of the reinforced body working cushion, unit: m;

[0045] (2) The vertical component T of the material pull-out force generated by the reinforced working cushion is:

[0046] T=T a sinθ

[0047] Where: T is the vertical component of the pull-out force generated by the reinforced body working cushion, in kPa;

[0048] T a —The designed pull-out resistance of the geocell used in the machine-made sand layer is 40 kPa for type A geocell;

[0049] θ—deformation angle of geocell in machine-made sand layer, 20° for type A geocell;

[0050] (3) Calculate the load diffusion effect p of the construction surface cushion:

[0051] p=τ′+T

[0052] Where: p is the load diffusion effect of the cushion layer on the construction surface, in kPa;

[0053] (4) Considering the diffusion effect of the reinforced body of the reinforced working cushion below the vertical drainage plate, the vertical additional stress caused by the large-area preloading is:

[0054] ΔP=r1h1+r2h2+r3h3-p

[0055] Where: ΔP—vertical additional stress caused by large-area preloading, unit kPa;

[0056] r1—Mineral powder density, unit: kN / m 3 ;

[0057] h1—mineral powder loading height, unit: m;

[0058] h2—composite filling thickness of construction waste and geocell, in m;

[0059] r2—weight of construction waste and geocell composite fill layer, unit: kN / m 3 ;

[0060] (5) The total settlement of ultra-soft sludge caused by heap preloading treatment is:

[0061]

[0062] Where: S is the total settlement of ultra-soft sludge caused by heap preloading treatment, unit: m;

[0063] m s — Sedimentation correction factor: for ultra-soft sludge, take 1.3 to 1.4;

[0064] E s —Compression modulus of super soft silt, in kPa, for super soft silt, the value is 1.3 to 1.4;

[0065] H—thickness of super soft silt layer, m.

[0066] (6) After 4 to 5 months of preloading, the consolidation degree of the ultra-soft silt layer reaches 85%, and the settlement of the ultra-soft silt layer during the construction period is S t =0.85*S.

[0067] The preferred technical solution of the present invention is as follows: the seepage barrier membrane in step S4 is a double rough HDPE seepage barrier membrane with a thickness of 1.5 mm, the plastic vertical drainage board is arranged in a square shape, and the head of each vertical drainage board is exposed 5 to 10 cm above the HDPE seepage barrier membrane; three layers of 6.3 mm thick composite geotextile drainage grids are laid in S4, and the head of the vertical drainage board is tied and connected with the reinforcement of the middle layer of composite geotextile grid; the non-woven geotextile in step S5 is 300 g / m 2 Non-woven geotextile.

[0068] Beneficial effects of the present invention:

[0069] (1) The present invention improves the preloading structure of ultra-soft sludge and proposes a preloading structure composed of three reinforced body systems, namely, a construction surface reinforced body structure, a drainage reinforced body structure, and an ultra-high reinforced body preloading structure, forming a fully flexible preloading structure, which is easy to construct, reduces construction costs, and saves construction time;

[0070] (2) The reinforced structure of the construction working surface of the present invention is composed of machine-made sand and geocells. The geocells have high strength and are superior to geogrids. Compared with fine sand or sea sand, machine-made sand has low cost, abundant sand sources, and high strength. The reinforced structure of the construction working surface improves the bearing capacity of the cushion layer of the construction working surface, and the settlement and deformation of subsequent construction machinery operations are small.

[0071] (3) The reinforced drainage structure of the present invention is composed of a double-roughened HDPE seepage barrier membrane and a three-layer composite drainage grid. The plastic drainage board is directly connected to the composite drainage grid. The bottom is waterproofed by a double-roughened HDPE seepage barrier membrane. The upper and lower surfaces of the seepage barrier membrane are rough surfaces, which not only play a waterproof role, but also play an anti-skid role, preventing the ultra-soft silt foundation from becoming unstable during graded loading.

[0072] (4) The ultra-high reinforced body loading structure of the present invention uses construction waste and geocells in the lower part and mineral powder in the upper part. The strength of the geocell in the ultra-high reinforced body loading structure is lower than that of the geocell in the cushion layer of the construction working surface. Under the premise of ensuring the stability of the foundation, the cost of the reinforced body system is saved; the construction waste is selected after crushing and screening, thereby realizing the recycling and reuse of the construction waste. The mineral powder is excavated after the pre-compression is completed, so as to achieve recycling and prevent the mineral powder from causing secondary pollution to the foundation.

[0073] (5) Before construction, the present invention determines the height of the pile load by calculating the preloading settlement of a large area of ​​pile load, and in the calculation process, the recent fill below the drainage system is considered as an additional stress load, and the load diffusion effect of the reinforced body is considered at the same time. The load diffusion effect of the reinforced body is composed of two parts: the vertical shear force of the reinforced body filler and the tensile force of the reinforced body material. The calculation method is simple and practical, and the calculation results are consistent with the measured results, which ensures that the pile load height is calculated accurately and is easy to promote and apply. BRIEF DESCRIPTION OF THE DRAWINGS

[0074] Figure 1 It is a schematic diagram of the super-high reinforced body preloading treatment structure in the present invention;

[0075] Figure 2 It is a schematic diagram of the structure of the drainage reinforcement body of the partition of the present invention;

[0076] Figure 3 It is a schematic diagram for calculating the vertical shear force τ generated by the working cushion layer of the reinforced body in the present invention;

[0077] Figure 4 1 is the measured settlement curve of the embodiment.

[0078] Figure 1 Middle: 1-super soft silt layer, 2-woven fabric layer, 3-reinforced composite layer, 4-vertical drainage board, 5-seepage membrane, 6-horizontal composite drainage net, 7-clay soil layer, 8-first non-woven fabric layer, 9-composite landfill layer, 10-second non-woven fabric layer, 11-mineral powder backfill layer. DETAILED DESCRIPTION

[0079] The present invention will be further described below in conjunction with the accompanying drawings and embodiments. Figures 1 to 4 The drawings are all of embodiments, which are drawn in a simplified manner and are only used for the purpose of clearly and concisely illustrating the embodiments of the present invention. The technical solutions shown in the following drawings are specific solutions of the embodiments of the present invention and are not intended to limit the scope of the invention claimed for protection. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0080] The embodiment provides a super-soft sludge non-drainage layer super-high reinforced body preloading treatment structure, such as Figure 1 and Figure 2 As shown, it includes a reinforced body working cushion layer, a drainage reinforced body structure and an ultra-high reinforced body loading structure layer; the reinforced body working cushion layer includes a woven cloth layer 2 laid on the top surface of the ultra-soft silt layer 1 and a reinforced composite layer 3 located above the woven cloth layer 2, and the reinforced composite layer 3 is composed of a type A geocell and a machine-made sand blowing fill layer. The woven cloth layer 2 is made of 150g / m 2 The reinforced composite layer 3 includes a bottom A-type geocell, a middle A-type geocell and a 1-2m thick machine-made sand blowing fill layer. The bottom A-type geocell is arranged on the top surface of the woven fabric layer 2, and the middle A-type geocell is located in the middle of the machine-made sand blowing fill layer. The A-type geocell in the reinforced composite layer 3 adopts a polyester (PET) tensile geocell, and the tensile strength limit value is not less than 180kN / m.

[0081] In the embodiment, the drainage reinforcement structure is as follows Figure 1 and Figure 2 As shown, it includes a seepage barrier membrane 5, a three-layer horizontal composite drainage net 6 and a plurality of vertical drainage boards 4. The vertical drainage board 4 is inserted into the ultra-soft silt layer 1, and its bottom end is embedded in the clay layer 7 at the bottom of the ultra-soft silt layer 1. The seepage barrier membrane 5 is laid on the top surface of the reinforced working cushion layer, and the multiple layers of horizontal composite drainage nets 6 are laid on the seepage barrier membrane 5 in sequence. The top of the vertical drainage board 4 is higher than the seepage barrier membrane 5 and is connected to the reinforcement of the middle layer horizontal composite drainage net 6; the vertical drainage board 4 is constructed by a plug-in machine to construct a vertical plastic drainage board, and the bottom of the plastic drainage board enters the clay layer by no less than 1.0m. The vertical drainage boards 4 are spaced 0.8 to 1.0m apart and arranged in a square shape; the seepage barrier membrane 5 is made of HDPE seepage barrier membrane with a thickness of no less than 1.5mm; the horizontal composite drainage net 6 is provided with three layers, and the vertical drainage board 4 is connected to the reinforcement of the middle layer horizontal composite drainage net 6. The density of the HDPE seepage barrier membrane is not less than 0.95g / cm 3 , the roughness height is not less than 0.3mm, the yield strength is not less than 25N / mm; the horizontal composite drainage net 6 adopts a 6.3mm thick composite geotextile drainage grid, and the longitudinal water conductivity is not less than 1*10 -3 m 2 / s, longitudinal tensile strength not less than 18kN / m, unit area mass not less than 200g / m 2 .

[0082] In the embodiment, Figure 1As shown, the ultra-high reinforced body loading structure layer includes a first non-woven fabric layer 8 laid on the top surface of the drainage reinforced body structure layer, a construction waste and geocell composite filling layer 9 stacked on the first non-woven fabric layer 8, a second non-woven fabric layer 10 laid on the top surface of the composite filling layer 9 and a mineral powder backfill layer 11 stacked above the second non-woven fabric layer 10; the composite filling layer 9 is composed of a construction waste impact rolling layer and a B-type geocell. The height of the composite landfill layer 9 is 3 to 6 meters, and the bottom and top layers are both construction waste impact rolling layers, with multiple layers of B-type geocells in the middle. Each construction waste impact rolling layer is a backfill rolling layer with a thickness of 0.8 to 1.2 meters formed by backfilling construction waste with a particle size not greater than 20 cm and then impact rolling. The construction waste is a filler with a particle size not greater than 20 cm formed by crushing granular masonry and cement concrete blocks; the height of the mineral powder backfill layer 11 is 1 to 3 meters, and the height of the mineral powder backfill layer 11 is less than the height of the composite landfill layer 9. The first non-woven fabric layer 8 and the second non-woven fabric layer 10 are both made of 300g / m 2 The non-woven geotextile, the B-type geocell adopts a polyethylene extruded geocell, and the tensile strength limit value is not less than 30kN / m.

[0083] In the embodiment, a super-high reinforced body is preloaded on a super-soft mud foundation. Before the preloading, the thickness of the composite filling of construction waste and geocell in the super-high reinforced body loading structure layer is set to h2 and the height of the mineral powder loading is set to h1, where h1 is 1 to 3m, h2 is 3 to 6m, and h 2＞ h1; combined with the current ground elevation H of the foundation to be treated d , Foundation treatment delivery surface elevation H s The settlement of the super-soft silt soil layer during the construction period S is calculated based on the requirements and the thickness of the reinforced working cushion h3. t ; By adjusting the set values ​​h1, h2, the design height h1, h2 and the calculated S t The value meets the following requirements:

[0084] h1+h2+h3>H s -H d , the construction period load is greater than the later design load, indicating an ultra-high load preload;

[0085] H d +h1+h2+h3-S t -h1=H s .

[0086] The settlement amount S of the ultra-soft silt layer t The calculation process is as follows:

[0087] (1) Under the action of the overlying load, the reinforced body in the reinforced working cushion layer of the construction surface is bent and deformed, compressive stress is generated in the upper part of the reinforced body, shear force is generated in the filler of the geocell, and tensile force is generated in the lower geocell. The load of the horizontal composite drainage network is ignored in the calculation process; the vertical shear force τ generated by the reinforced working cushion layer is:

[0088]

[0089] Where: τ-vertical shear force generated by the reinforced body working cushion, unit kPa;

[0090] -Internal friction angle of the reinforced working cushion filler, unit: °; for machine-made sand, take 25°;

[0091] K - passive earth pressure coefficient,

[0092] σ v -Self-weight load of the reinforced working cushion;

[0093] The calculation process of the self-weight load of the reinforced working cushion layer is as follows:

[0094] σ v =r3z

[0095] r3-weight of the reinforced body working cushion filler, unit: kN / m 3 ;

[0096] z-the vertical elevation of the reinforced body working cushion from the top to the bottom; the elevation of the top surface of the reinforced body working cushion is 0, and the elevation of the bottom surface of the reinforced body working cushion is h3;

[0097] The vertical shear force τ′ of the reinforced body working cushion filler is taken as the average value of the top and bottom surfaces, and the top surface height z is taken as 0, that is, the self-weight load σ of the top surface of the reinforced body working cushion v顶 = 0, vertical shear force τ on the top surface of the reinforced body working cushion 顶 =0, then:

[0098] τ′=1 / 2(τ 顶 +τ 底 )=1 / 2τ 底

[0099]

[0100] σ v底 =r3 h3

[0101] Based on this calculation:

[0102]

[0103] Where: r3-weight of the reinforced body working cushion filler, unit kN / m 3 ;

[0104] h3-the thickness of the reinforced body working cushion, in m;

[0105] (2) The vertical component T of the material pull-out force generated by the reinforced working cushion is:

[0106] T=T a sinθ

[0107] Where: T-vertical component of the pull-out force generated by the reinforced body working cushion, unit kPa;

[0108] T a - The designed pull-out resistance of the geocell used in the machine-made sand layer is 40 kPa for type A geocell;

[0109] θ-deformation angle of geocell in the machine-made sand layer, 20° for type A geocell;

[0110] (3) Calculate the load diffusion effect p of the construction surface cushion:

[0111] p=τ′+T

[0112] Where: p-load diffusion effect of the cushion layer on the construction working surface, unit kPa;

[0113] (4) Considering the diffusion effect of the reinforced body of the reinforced working cushion below the vertical drainage plate, the vertical additional stress caused by the large-area preloading is:

[0114] ΔP=r1h1+r2h2+r3h3-p

[0115] Where: ΔP-vertical additional stress caused by large-area preloading, unit kPa;

[0116] r1- mineral powder density, unit kN / m 3 ;

[0117] h1—mineral powder loading height, unit: m;

[0118] h2-the thickness of the composite landfill of construction waste and geocell, in m;

[0119] r2- Construction waste and geocell composite fill weight, unit kN / m 3 ;

[0120] (5) The total settlement of ultra-soft sludge caused by heap preloading treatment is:

[0121]

[0122] Where: S is the total settlement of ultra-soft sludge caused by preloading treatment, unit: m;

[0123] m s - Sedimentation correction factor: for ultra-soft sludge, take 1.3 to 1.4;

[0124] E s -Compression modulus of super soft sludge, in kPa, for super soft sludge, the value is 1.3 to 1.4;

[0125] H-thickness of super soft silt layer, m.

[0126] (6) After 4 to 5 months of preloading, the consolidation degree of the ultra-soft silt layer reaches 85%, and the settlement of the ultra-soft silt layer during the construction period is S t =0.85*S.

[0127] The results of the above calculations are shown in Tables 1 to 3, wherein Table 1 is the calculation parameters of the ultra-high heap load preloading treatment structure in the embodiment:

[0128] Table 1 Calculation parameters of super-high load preloading reinforced structure

[0129] r1(kN / m3) h1(m) r2(kN / m3) h2(m) r3(kN / m3) h3 φ(°) θ(°) 23 2 20 4 18.5 1 25 20

[0130] Table 2 is the calculation results of the additional stress of super-high preloading in the embodiment:

[0131] Table 2 Calculation values ​​of additional stress for super-high preloading

[0132] K(kPa) τ′(kPa) T(kPa) p(kPa) ΔP(kPa) 2.46 10.63 13.68 24.31 120.19

[0133] Table 3 is the calculation results of the super-high preloading settlement in the embodiment:

[0134] Table 3 Calculated values ​​of settlement of super-high pile load preloading

[0135] ms Es(kPa) H(m) S(m) St(m) 1.35 2000 20 1.62 1.38

[0136] In the embodiment, the elevation H of the top surface of the sludge d is 0.00m, the elevation of the foundation treatment delivery surface is H s It is 3.62m. According to the calculation results in Tables 1 to 3, it meets the following requirements:

[0137] H d +h1+h2+h3-S t -h1=0+2+4+1-1.38-3=3.62m

[0138] h1+h2+h3>H s -H d

[0139] The height of the mineral powder pile is determined to be 2m; the thickness of the composite pile of construction waste and geocell is 4m; after determining the above filling parameters, the construction can be carried out according to the following steps:

[0140] S1. Determine the foundation treatment area, determine the construction zone, and start construction;

[0141] S2. Build a foam board on the top surface of the ultra-soft silt layer and lay a layer of 150g / m 2 Woven cloth, and then lay a layer of A-type geocell on the woven cloth. The connection of A-type geocell is spliced. After the laying is completed, 50cm of machine-made sand is blown in. Then, another layer of A-type geocell is laid. The connection of A-type geocell is spliced ​​in, and 50cm of machine-made sand is blown in again.

[0142] S4. Lay a layer of 1.5mm thick double rough surface HDPE seepage barrier membrane, and then use a plate inserting machine to construct plastic vertical drainage board. The bottom of the plastic drainage board penetrates the ultra-soft silt layer and enters the clay soil layer by no less than 1.0m. The vertical drainage board spacing is 0.8-1.0m, arranged in a square, and the board head is 5-10cm higher than the HDPE seepage barrier membrane;

[0143] S5: Lay three layers of composite geotextile drainage grids, tie and connect the head of the vertical drainage board with the composite geotextile drainage grid of the middle layer, and then use the seepage-proof membrane to wrap the four sides of the vertical drainage board and weld it with the seepage-proof membrane on the top of the machine-made sand to ensure the water-proof effect;

[0144] S6. Lay a layer of 300g / m on the top surface of the top composite geotextile drainage grid. 2 Non-woven geotextile, start backfilling construction waste, first backfill 1m of construction waste, impact compaction, lay a layer of type B geocell, then backfill 1m of construction waste, impact compaction, and lay another layer of type B geocell, repeat the above steps to make the composite filling thickness of construction waste and geocell 4m, and lay three layers of polyethylene geocell;

[0145] S6. Lay another layer of 300g / m on the top of the top layer of construction waste landfill compaction. 2 Non-woven geotextile, filled with 2m mineral powder, fully loaded and preloaded for 4 months, and the settlement during the construction period was measured. Figure 3 As shown in the figure, the measured settlement during the construction period after 4 months of preloading is 1.39m, which is close to the calculated value St = 1.38m. This shows that the calculation results of the above calculation method are more accurate. After the foundation treatment reaches the preloading unloading condition, the mineral powder is excavated and the 300g / m 2 Non-woven geotextile.

[0146] The method of the present invention has good effect in reinforcing and treating ultra-soft sludge, reduces sand consumption, saves construction cost, has clear calculation principles and methods, is convenient for design and engineering application, is simple in construction, and has broad prospects for engineering application.

[0147] In summary, the content of the present invention is not limited to the above-mentioned embodiments, and people with insight in the same field can easily propose other embodiments within the technical guiding ideology of the present invention, but such embodiments are all included in the scope of the present invention.

Claims

1. A super-soft sludge non-drainage layer super-high reinforced body preloading treatment structure, characterized by: The treatment structure includes a reinforced body working cushion layer, a drainage reinforced body structure and an ultra-high reinforced body loading structure layer; The reinforced working cushion layer comprises a woven fabric layer (2) laid on the top surface of the ultra-soft silt layer (1) and a reinforced composite layer (3) located above the woven fabric layer (2), wherein the reinforced composite layer (3) is composed of a composite of an A-type geocell and a machine-made sand blowing fill layer; The drainage reinforcement structure comprises a seepage-proof membrane (5), a multi-layer horizontal composite drainage net (6) and a plurality of vertical drainage boards (4), wherein the vertical drainage board (4) is inserted into the ultra-soft silt layer (1), and the bottom end thereof is embedded in the clay layer (7) at the bottom of the ultra-soft silt layer (1), the seepage-proof membrane (5) is laid on the top surface of the reinforced body working cushion layer, and the multi-layer horizontal composite drainage net (6) is laid in sequence above the seepage-proof membrane (5), and the top end of the vertical drainage board (4) is higher than the seepage-proof membrane (5) and is connected to the reinforcement material of the intermediate layer horizontal composite drainage net (6); The ultra-high reinforced body loading structure layer comprises a first non-woven fabric layer (8) laid on the top surface of the drainage reinforced body structure layer, a construction waste and geocell composite filling layer (9) stacked on the first non-woven fabric layer (8), a second non-woven fabric layer (10) laid on the top surface of the composite filling layer (9), and a mineral powder backfill layer (11) stacked on top of the second non-woven fabric layer (10); the composite filling layer (9) is composed of a construction waste impact rolling layer and a B-type geocell.

2. The ultra-soft sludge non-drainage layer ultra-high reinforced body preloading treatment structure according to claim 1 is characterized by: The woven fabric layer (2) is made of 150g / m 2 The reinforced composite layer (3) comprises a bottom A-type geocell, a middle A-type geocell and a machine-made sand blowing fill layer with a thickness of 1 to 2 m, the bottom A-type geocell being arranged on the top surface of the woven fabric layer (2), and the middle A-type geocell being located in the middle of the machine-made sand blowing fill layer.

3. The ultra-soft sludge drainage-free layer ultra-high reinforced body preloading treatment structure according to claim 1 is characterized by: The vertical drainage board (4) is constructed of vertical plastic drainage boards using a plug-in machine. The bottom of the plastic drainage board enters the clay layer by no less than 1.0 m. The vertical drainage boards (4) are spaced 0.8 to 1.0 m apart and arranged in a square. The seepage-proof membrane (5) uses a HDPE seepage-proof membrane with a thickness of no less than 1.5 mm. The horizontal composite drainage net (6) is provided with three layers, and the vertical drainage board (4) is connected to the reinforcement of the middle layer horizontal composite drainage net (6).

4. The ultra-soft sludge drainage-free layer ultra-high reinforced body preloading treatment structure according to claim 1 is characterized by: The height of the composite landfill layer (9) is 3 to 6 m, and the bottom and top layers thereof are both construction waste impact compaction layers, with multiple layers of B-type geocells arranged in the middle. Each construction waste impact compaction layer is a backfill compaction layer with a thickness of 0.8 to 1.2 m formed by backfilling construction waste with a particle size not greater than 20 cm and then impact compacting it. The construction waste is a filler with a particle size not greater than 20 cm formed by crushing granular bricks and cement concrete blocks. The height of the mineral powder backfill layer (11) is 1 to 3 m, and the height of the mineral powder backfill layer (11) is less than the height of the composite landfill layer (9).

5. The ultra-soft sludge non-drainage layer ultra-high reinforced body preloading treatment structure according to claim 1 or 2, characterized in that: The A-type geocell in the reinforced composite layer (3) adopts a polyester tensile geocell, and the tensile strength limit value is not less than 180 kN / m.

6. The ultra-soft sludge non-drainage layer ultra-high reinforced body preloading treatment structure according to claim 3 is characterized by: The density of the HDPE barrier membrane is not less than 0.95 g / cm 3 , the roughness height is not less than 0.3mm, and the yield strength is not less than 25N / mm; the horizontal composite drainage net (6) adopts a 6.3mm thick composite geotextile drainage grid, and the longitudinal water conductivity is not less than 1*10 - 3 m 2 / s, longitudinal tensile strength not less than 18kN / m, unit area mass not less than 200g / m 2 .

7. The ultra-soft sludge non-drainage layer ultra-high reinforced body preloading treatment structure according to claim 1 or 4, characterized in that: The first non-woven fabric layer (8) and the second non-woven fabric layer (10) are both made of 300 g / m 2 The non-woven geotextile, the B-type geocell adopts a polyethylene extruded geocell, and the tensile strength limit value is not less than 30kN / m.

8. A method for preloading and preloading of ultra-high reinforced bodies in ultra-soft sludge without drainage layers, characterized in that: The treatment method adopts the ultra-soft sludge non-drainage layer ultra-high reinforced body preloading treatment structure according to any one of claims 1 to 7 for preloading, which specifically comprises the following steps: S1. Set the composite filling thickness of construction waste and geocell in the super-high reinforced body loading structure layer to h2 and the mineral powder loading height to h1, where h1 is 1 to 3m, h2 is 3 to 6m and h 2＞ h1; combined with the current ground elevation H of the foundation to be treated d , Foundation treatment delivery surface elevation H s The settlement of the super-soft silt soil layer during the construction period S is calculated based on the requirements and the thickness of the reinforced working cushion h3. t ; By adjusting the set values ​​h1, h2, the design height h1, h2 and the calculated S t The value meets the following requirements: h1+h2+h3>H s -H d H d +h1+h2+h3-S t -h1=H s In the formula, S t Settlement of super-soft silt soil layer during construction period; The design values ​​h1 and h2 that meet the above requirements are used as the height of the mineral powder pile and the thickness of the composite filling of construction waste and geocell in the actual pile; S2. Determine the foundation treatment area, determine the construction zones, and start construction; S3. A foam board is set up on the top surface of the ultra-soft silt layer, and a layer of woven cloth is laid, and then a layer of type A geocell is laid on the woven cloth. The connection of the type A geocell is spliced. After the laying is completed, 50cm to 60cm of machine-made sand is blown in, and then another layer of type A geocell is laid. The connection of the type A geocell is spliced, and 50cm to 60cm of machine-made sand is blown in again; S4. Lay a layer of seepage-proof membrane with a thickness of not less than 1.5 mm, and then use a plate inserter to construct a plastic vertical drainage board. The bottom of the plastic drainage board penetrates the ultra-soft silt layer and enters the clay layer by not less than 1.0 m. The spacing between the vertical drainage boards is 0.8 to 1.0 m, and the board head is higher than the seepage-proof membrane; lay a multi-layer composite geotextile drainage grid, tie and connect the board head of the vertical drainage board with the composite geotextile drainage grid of the middle layer, and then use a seepage-proof membrane to wrap the four sides of the vertical drainage board, and seal it with the seepage-proof membrane on the top of the machine-made sand to ensure the water-proof effect; S5. Lay a layer of non-woven geotextile on the top surface of the top composite geodrainage grid, and start backfilling construction waste. First, backfill 0.8 to 1 m of construction waste, impact and roll, lay a layer of type B geocell, then backfill 0.8 to 1 m of construction waste, impact and roll, and then lay a layer of type B geocell. Repeat the above steps until the composite filling thickness of construction waste and geocell reaches the composite filling thickness h2 of construction waste and geocell determined in step S1; S6. Lay another layer of non-woven geotextile on the top surface of the topmost construction waste landfill compaction layer, and start to fill the mineral powder. After the mineral powder filling height reaches the mineral powder loading height h1 determined in step S1, preloading is performed.

9. A method for preloading and loading of ultra-high reinforced bodies in ultra-soft sludge non-drainage layers according to claim 8, characterized in that: The settlement amount S of the ultra-soft silt soil layer during the construction period in step S1 t The calculation process is as follows: (1) Under the action of the overlying load, the reinforced body in the reinforced working cushion layer of the construction surface is bent and deformed, compressive stress is generated in the upper part of the reinforced body, shear force is generated in the filler of the geocell, and tensile force is generated in the lower geocell. The load of the horizontal composite drainage network is ignored in the calculation process; the vertical shear force τ generated by the reinforced working cushion layer is: Where: τ-vertical shear force generated by the reinforced body working cushion, unit kPa; -Internal friction angle of the reinforced body working cushion filler, unit: °; for machine-made sand, 25°; K - passive earth pressure coefficient, σ v -Self-weight load of the reinforced working cushion; The calculation process of the self-weight load of the reinforced working cushion layer is as follows: s v =r3z r3-weight of the reinforced body working cushion filler, unit: kN / m 3 ; z-the vertical elevation of the reinforced body working cushion from the top to the bottom; the elevation of the top surface of the reinforced body working cushion is 0, and the elevation of the bottom surface of the reinforced body working cushion is h3; The vertical shear force τ′ of the reinforced body working cushion filler is taken as the average value of the top and bottom surfaces, and the top surface height z is taken as 0, that is, the self-weight load σ of the top surface of the reinforced body working cushion v顶 = 0, vertical shear force τ on the top surface of the reinforced body working cushion 顶 =0, then: τ′=1 / 2(τ 顶 +t 底 )=1 / 2τ 底 σ v底 =r3 h3 Based on this calculation: Where: r3-weight of the reinforced body working cushion filler, unit kN / m 3； h3-the thickness of the reinforced body working cushion, in m; (2) The vertical component T of the material pull-out force generated by the reinforced working cushion is: T=T a ·sinθ Where: T-vertical component of the pull-out force generated by the reinforced body working cushion, unit kPa; T a - The designed pull-out resistance of the geocell used in the machine-made sand layer is 40 kPa for type A geocell; θ-deformation angle of geocell in the machine-made sand layer, 20° for type A geocell; (3) Calculate the load diffusion effect p of the construction surface cushion: p=τ′+T Where: p-load diffusion effect of the cushion layer on the construction working surface, unit kPa; (4) Considering the diffusion effect of the reinforced body of the reinforced working cushion below the vertical drainage plate, the vertical additional stress caused by the large-area preloading is: ΔP=r1h1+r2h2+r3h3-p Where: ΔP-vertical additional stress caused by large-area preloading, unit kPa; r1- mineral powder density, unit kN / m 3 ; h1—mineral powder loading height, unit: m; h2-the thickness of the composite landfill of construction waste and geocell, in m; r2- Construction waste and geocell composite fill weight, unit kN / m 3 ; (5) The total settlement of ultra-soft sludge caused by heap preloading treatment is: Where: S is the total settlement of ultra-soft sludge caused by preloading treatment, unit: m; m s - Sedimentation correction factor: for ultra-soft sludge, take 1.3 to 1.4; E s —Compression modulus of super soft silt, in kPa, for super soft silt, the value is 1.3 to 1.4; H—thickness of super soft silt layer, m. (6) After 4 to 5 months of preloading, the consolidation degree of the ultra-soft silt layer reaches 85%, and the settlement of the ultra-soft silt layer during the construction period is S t =0.85*S.

10. The method for preloading and loading of ultra-high reinforced bodies in ultra-soft sludge non-drainage layers according to claim 8, characterized in that: The seepage barrier membrane in step S4 is a double-roughened HDPE seepage barrier membrane with a thickness of 1.5 mm. The plastic vertical drainage boards are arranged in a square shape, and the head of each vertical drainage board is exposed 5 to 10 cm above the HDPE seepage barrier membrane. Three layers of 6.3 mm thick composite geogrid drainage grids are laid in S4, and the head of the vertical drainage board is tied and connected to the reinforcement of the middle layer of composite geogrid. The non-woven geotextile in step S5 is 300 g / m 2 Non-woven geotextile.

Images