Shield excavation and soil body settlement monitoring simulation test platform and simulation test method
阅读说明：本技术 盾构开挖与土体沉降监测模拟试验平台及模拟试验方法 (Shield excavation and soil body settlement monitoring simulation test platform and simulation test method ) 是由 江华 程晋国 李宏亮 江玉生 李继东 王高敏 戈玮 赵亮 唐飞鹏 冯一帆 李加恒 于 2019-12-03 设计创作，主要内容包括：本发明涉及一种盾构开挖与土体沉降监测模拟试验平台及模拟试验方法,其模拟试验平台包括箱体、开挖模拟系统和土体沉降监测系统,所述开挖模拟系统安装于所述箱体内,包括内置钢圆筒,该内置钢圆筒外围均匀间隔布置若干个与其同心的环形隔板,相邻环形隔板之间安装与该内置钢圆筒同心的外环水层和内环水层；所述土体沉降监测系统包括至少一排单点位移计。本发明至少能够模拟盾构施工开挖间隙、盾尾间隙充填情况对地层沉降的控制效果,进一步能够研究盾构开挖引起土体的沉降规律,以及对土体沉降监测结果进行修正并研究修正规律。该平台制作组装方便,可拆除重复利用。(The invention relates to a shield excavation and soil body settlement monitoring simulation test platform and a simulation test method, wherein the simulation test platform comprises a box body, an excavation simulation system and a soil body settlement monitoring system, the excavation simulation system is arranged in the box body and comprises a built-in steel cylinder, a plurality of annular partition plates concentric with the built-in steel cylinder are uniformly arranged at the periphery of the built-in steel cylinder at intervals, and an outer annular water layer and an inner annular water layer concentric with the built-in steel cylinder are arranged between the adjacent annular partition plates; the soil body settlement monitoring system comprises at least one row of single-point displacement meters. The method can simulate the control effect of the shield construction excavation gap and the shield tail gap filling condition on the stratum settlement at least, further study the settlement rule of the soil body caused by shield excavation, correct the soil body settlement monitoring result and study the correction rule. The platform is convenient to manufacture and assemble and can be disassembled and reused.)
1. The utility model provides a shield constructs excavation and soil body settlement monitoring analogue test platform which characterized in that includes box, excavation analog system and soil body settlement monitoring system, wherein:
undisturbed soil is filled in the box body;
the excavation simulation system is arranged in the box body and comprises a built-in steel cylinder, the built-in steel cylinder is used as a bearing foundation of the excavation simulation system, a plurality of annular partition plates concentric with the built-in steel cylinder are uniformly arranged at intervals on the periphery of the built-in steel cylinder, an outer annular water layer and an inner annular water layer concentric with the built-in steel cylinder are arranged between the adjacent annular partition plates, the outer annular water layer is provided with a water injection hole and a grouting hole communicated with the inner part of the outer annular water layer, and the inner annular water layer is;
the soil body settlement monitoring system comprises at least one row of single-point displacement meters, and the single-point displacement meters are buried in the undisturbed soil body.
2. The simulation test platform according to claim 1, wherein the box body is a three-dimensional steel plate soil box with an open upper portion, and the left and right side plates of the soil box are respectively provided with a vertical sliding groove for placing two ends of the built-in steel cylinder, so that the built-in steel cylinder can slide up and down in the vertical sliding grooves, and the arrangement height of the excavation simulation system is adjusted.
3. The simulation test platform of claim 2, wherein the vertical chute is configured with a vertical chute closure plate for enclosing the interior fill.
4. The simulation test platform of claim 1, wherein the soil settlement monitoring system comprises a first row of single point displacement meters and a second row of single point displacement meters, the periphery of the first row of single point displacement meters is backfilled with undisturbed soil, and the ultra-deep section of the hole of the second row of single point displacement meters is backfilled with test soil.
5. The simulation test platform of claim 4, wherein the first row of single point displacement meters and the second row of single point displacement meters are respectively fixed on the upper part of the box body by single point displacement meter fixing rods.
6. The simulation test platform of claim 4, wherein the first row of single point displacement meters and the second row of single point displacement meters are respectively provided with a plurality of single point displacement meters, and the burying depths of the single point displacement meters are different.
7. The simulation test platform of claim 1, wherein the annular baffles are spaced apart by the width of the shield tunnel simulation segment.
8. The simulation test platform of claim 1, wherein the built-in steel cylinder of the excavation simulation system is fixed at a test height at both ends by support rails.
9. A method of simulation testing of a simulation testing platform according to any of the claims 1-8, characterized in that it comprises the steps of:
s1: simulating the beginning of shield tunneling;
s2: water is discharged from the water layer of the outer ring of the previous ring to simulate an excavation gap generated by cutter excavation;
s3: after the excavation gap acts for a certain time, water is discharged to the previous annular water layer to simulate the shield tail gap generated by shield tail separation;
s4: after the excavation gap and the shield tail gap act together for a certain time, grouting the water layer of the outer ring of the previous ring, and simulating different filling degrees by designing and controlling the grouting amount;
s5: repeating the steps S2-S4, and carrying out water drainage and grouting filling on the water layer of the next ring which reaches the designed excavation time;
s6: and repeating the step S5, and sequentially carrying out simulated excavation to realize the propulsion of the shield by setting the actual time difference between water discharge and grouting filling of the water-surrounding layers of different rings.
10. The simulation test method according to claim 9, wherein the excavation gap and the shield tail gap are fixed, the single-point displacement meter is used for acquiring the settlement data of soil bodies at different depths, and the correction rules of the settlement monitoring values of the single-point displacement meter at different ultra depths are researched by comparing the settlement value difference of the undisturbed soil and the ultra-deep backfill soil in the soil layer at the same depth.
Technical Field
The invention relates to the technical field of shield construction, in particular to a shield excavation and soil body settlement monitoring simulation test platform and a simulation test method.
Background
One of the important measures for controlling the settlement when the shield method is adopted in the subway tunnel construction is grouting filling, shield tail gap filling is adopted in almost most of the projects at present, the excavation gap filling is rarely considered, and the stratum settlement effect caused by the excavation gap cannot be ignored in projects with high settlement requirements. High-precision and automatic monitoring of stratum displacement caused by shield construction is an important guarantee for realizing micro-disturbance and micro-settlement control when a shield passes through a major risk source, and stratum deep-layer displacement monitoring is increasingly carried out in actual engineering at present. At present, magnetic ring type displacement meters, multipoint displacement meters and single-point displacement meters are adopted for deep level displacement monitoring, and no matter which monitoring equipment is adopted, the equipment needs to be punched and buried in the stratum and backfilled with sand for monitoring. The on-site drilling is ultra-deep, namely the drilling depth exceeds the design depth, the backfill sand of the ultra-deep part is greatly different from the original soil, and the displacement meter actually monitors the sedimentation value of the backfill sand layer in the deep hole sleeve instead of the actual sedimentation of the original stratum at the position.
In order to find out the control effect of the filling degree of the shield excavation gap and the shield tail gap on the stratum settlement, eliminate the settlement difference between the backfill sand and the surrounding stratum or establish the comparison relation between the filling degree and the elastic modulus of the filling material in numerical simulation, it is important to design a similar simulation experiment platform which can simulate the shield excavation, grouting and filling and can also carry out deep soil settlement monitoring and correction.
Disclosure of Invention
The invention aims to overcome the defects of the prior art and provides a shield excavation and soil body settlement monitoring simulation test platform and a simulation test method, which can at least simulate the control effect of the shield construction excavation gap and the shield tail gap filling condition on the stratum settlement, further study the soil body settlement rule caused by the shield excavation, correct the soil body settlement monitoring result and study the correction rule. The platform is convenient to manufacture and assemble and can be disassembled and reused.
The invention provides a shield excavation and soil body settlement monitoring simulation test platform, which comprises a box body, an excavation simulation system and a soil body settlement monitoring system, wherein:
undisturbed soil is filled in the box body;
the excavation simulation system is arranged in the box body and comprises a built-in steel cylinder, the built-in steel cylinder is used as a bearing foundation of the excavation simulation system, a plurality of annular partition plates concentric with the built-in steel cylinder are uniformly arranged at intervals on the periphery of the built-in steel cylinder, an outer annular water layer and an inner annular water layer concentric with the built-in steel cylinder are arranged between the adjacent annular partition plates, the outer annular water layer is provided with a water injection hole and a grouting hole communicated with the inner part of the outer annular water layer, and the inner annular water layer is;
the soil body settlement monitoring system comprises at least one row of single-point displacement meters, and the single-point displacement meters are buried in the undisturbed soil body.
As an improvement, the box body is a three-dimensional steel plate soil box with an open upper part, and the left side plate and the right side plate of the soil box are respectively provided with a vertical sliding groove for placing two ends of the built-in steel cylinder, so that the built-in steel cylinder can slide up and down in the vertical sliding grooves, and the arrangement height of the excavation simulation system is adjusted.
As an improvement, the vertical sliding groove is provided with a vertical sliding groove sealing plate for sealing the inner filling soil.
As an improvement, the soil body settlement monitoring system comprises a first row of single-point displacement meters and a second row of single-point displacement meters, the periphery of the first row of single-point displacement meters is backfilled with original soil, and the ultra-deep section of the hole of the second row of single-point displacement meters is backfilled with test soil.
As an improvement, the first row of single-point displacement meters and the second row of single-point displacement meters are respectively fixed on the upper part of the box body by single-point displacement meter fixing rods.
As an improvement, the first row of single-point displacement meters and the second row of single-point displacement meters are respectively provided with a plurality of single-point displacement meters, and the embedding depths of the single-point displacement meters are different.
As an improvement, the spacing distance of the annular partition plates is the width of the simulated duct pieces of the shield tunnel.
As an improvement, two ends of a built-in steel cylinder of the excavation simulation system are fixed at a test height through supporting cross rods.
The invention also provides a simulation test method according to the simulation test platform, which comprises the following steps:
s1: simulating the beginning of shield tunneling;
s2: water is discharged from the water layer of the outer ring of the previous ring to simulate an excavation gap generated by cutter excavation;
s3: after the excavation gap acts for a certain time, water is discharged to the previous annular water layer to simulate the shield tail gap generated by shield tail separation;
s4: after the excavation gap and the shield tail gap act together for a certain time, grouting the water layer of the outer ring of the previous ring, and simulating different filling degrees by designing and controlling the grouting amount;
s5: repeating the steps S2-S4, and carrying out water drainage and grouting filling on the water layer of the next ring which reaches the designed excavation time;
s6: and repeating the step S5, and sequentially carrying out simulated excavation to realize the propulsion of the shield by setting the actual time difference between water discharge and grouting filling of the water-surrounding layers of different rings.
As an improvement, the excavation gap and the shield tail gap are set to be fixed, the settlement data of soil bodies at different depths are collected through the single-point displacement meter, the difference of settlement values of the single-point displacement meter of original state soil and ultra-deep backfill soil in the soil layer at the same depth is compared, and the correction rules of the settlement monitoring values of the single-point displacement meter at different ultra depths are researched.
Has the advantages that: after the technical scheme is adopted, compared with the prior art, the invention has the following technical effects:
(1) the invention simulates the pipe piece through a fixed built-in steel cylinder, simulates the excavation gap through an outer annular water layer, simulates the shield tail gap through an inner annular water layer, and simulates the filling condition through grouting.
(2) And (4) sequentially simulating excavation to realize the moving propulsion of the shield by the actually set time difference of water drainage and grouting filling of the water-circulating layers of different rings.
(3) The single-point displacement meter is used for monitoring soil body settlement in a combined mode, under the conditions that different excavation gaps and shield tail gaps are set, different-depth soil body settlement data are collected through the single-point displacement meter, and the settlement rule of the soil body caused by shield tunnel excavation is researched.
(4) The single-point displacement meter is combined to monitor soil body settlement, the excavation gap and the shield tail gap are set under a certain condition, the single-point displacement meter is used for collecting the soil body settlement data of different depths, the difference of settlement difference values of the original state soil and the ultra-deep backfill soil in the same depth soil layer is compared, and the correction rule of the monitoring settlement values of the drilling single-point displacement meter of different ultra depths is researched.
Drawings
FIG. 1 is a perspective view of one embodiment of a simulation test platform according to the present invention;
FIG. 2 is a schematic diagram of the construction of one embodiment of the excavation simulation system of the present invention;
FIG. 3 is a schematic illustration of the construction gap according to one embodiment of the present invention.
The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the invention and together with the description serve to explain the principles of the invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention more apparent, the embodiments of the present invention are described in further detail below with reference to the embodiments and the accompanying drawings. The exemplary embodiments and descriptions of the present invention are provided to explain the present invention, but not to limit the present invention.
In the description of the present invention, it is to be understood that the terms "upper", "lower", "front", "rear", "left", "right", "top", "bottom", "inner", "outer", and the like, indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only for convenience in describing the present invention and simplifying the description, but do not indicate or imply that the device, component, or structure referred to must have a particular orientation, be constructed or operated in a particular orientation, and should not be construed as limiting the present invention.
It will be further understood that the terms "comprises/comprising," "consists of … …," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a product, apparatus, process, or method that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such product, apparatus, process, or method if desired. Without further limitation, an element defined by the phrases "comprising/including … …," "consisting of … …," or "comprising" does not exclude the presence of other like elements in a product, device, process, or method that comprises the element.
The following will further explain the specific implementation method of the present invention with reference to the attached drawings.
In the invention, "left" refers to the left side facing the longitudinal direction of the view roadway, "right" refers to the right side facing the longitudinal direction of the view roadway, "up" refers to the side facing the view and close to the top plate of the roadway, "down" refers to the side facing the view and close to the bottom plate of the roadway, "inner" refers to the side facing the view and close to the underground reservoir, "outer" refers to the side facing the view and close to the roadway, "longitudinal" refers to the direction parallel to the trend of the roadway, and "transverse" refers to the direction perpendicular to the trend of the roadway.
Referring to fig. 1, fig. 1 is a perspective view of a three-dimensional structure of a shield excavation and soil body settlement monitoring simulation test platform provided by the invention, and the three-dimensional structure comprises a
Referring specifically to fig. 1, as a specific example, according to the principle of similarity simulation, a
In a specific example, the left side plate and the right side plate of the soil box are respectively provided with a vertical sliding
In one embodiment, the
In a specific example, referring to fig. 2, the
An outer
Wherein the inner
Referring again to fig. 1, in one example, the soil
In a modified example, the soil
In one example, the first row of single point displacement meters and the second row of single point displacement meters are respectively fixed on the upper part of the box body by a single point displacement
In a modified example, the first row of single-point displacement meters and the second row of single-point displacement meters are respectively provided with a plurality of single-point displacement meters, and the burying depths of the single-point displacement meters are different.
Two rows of single-point displacement meters are arranged on the upper portion of the box body and are fixed through single-point displacement meter fixing rods respectively, the periphery of the first row of single-point displacement meters is backfilled with original state soil, the hole of the second row of single-point displacement meters is backfilled with experimental soil, drilling monitoring experiments under different ultra-deep conditions are simulated and used as contrast experiments, the settlement rule of a soil body caused by shield excavation is researched, the soil body settlement monitoring result is corrected, and the correction rule is researched, and the method is further specifically explained later.
In the invention, an excavation simulation system (taking a three-ring simulation segment as an example in the figure) can be fixed on vertical sliding grooves on two sides of a box body through a built-in steel cylinder, and the test height is adjusted through a supporting
Continuing to refer to fig. 3, a
With reference to fig. 2 and fig. 3, the present invention further provides a simulation test method according to the simulation test platform, which includes the following steps:
s1: simulating the beginning of shield tunneling;
s2: an
s3: after the excavation gap acts for a certain time, a
s4: after the excavation gap and the shield tail gap act together for a certain time, grouting the water layer of the outer ring of the previous ring, and simulating different filling degrees by designing and controlling the grouting amount;
s5: repeating the steps S2-S4, and carrying out water drainage and grouting filling on the water layer of the next ring which reaches the designed excavation time;
s6: and repeating the step S5, and sequentially carrying out simulated excavation to realize the propulsion of the shield by setting the actual time difference between water discharge and grouting filling of the water-surrounding layers of different rings.
The working principle of the invention is as follows:
① geological condition similarity processing, according to the buried depth, tunnel diameter and soil layer condition of the engineering actual investigation, according to the proper similarity ratio K (the ratio of the on-site actual value and the indoor simulation value), determining the parameters of the simulation experiment.
② the working condition of the shield machine is determined by calculating the appropriate grouting pressure through the stratum property simulated by the indoor experiment, and setting the shield excavation gap value and the shield tail gap value by combining the shield construction parameters.
③ device building, single point displacement meter arranging and wiring (one row of undisturbed soil and one row of ultra-deep drilling hole manual backfill soil), and filling operation.
When the single-point displacement meter for simulating ultra-deep backfill is installed, a PVC pipe can be used as a sleeve to directly sleeve the single-point displacement meter inside, backfill is filled inside, original filling soil is filled outside, and finally the sleeve is removed. The cylinder short cylinder can also be used for shielding and filling one section by one section, and then the cylinder short cylinder can be pulled up while filling. And the ultra-deep section of the sleeve is backfilled with soil, and the rest is undisturbed soil, so that different soil layers on site are simulated.
The installation of the single-point displacement meter for simulating undisturbed soil can be realized without a sleeve, and the undisturbed soil is directly filled in a whole box layer by layer.
④ excavation simulation, according to design value, a shield machine is simulated to firstly drain water to the outer
When the water drainage and grouting filling of the water-circulating layer of the current ring of simulation pipe piece are carried out, the water drainage and grouting filling are carried out on the water-circulating layer of the next ring which reaches the designed excavation time, and the simulated excavation is carried out in sequence to realize the moving propulsion of the shield through the actually set time difference of the water drainage and grouting filling of the water-circulating layers of different rings, namely the movement of the excavation gap, the shield tail gap and the grouting filling is simulated.
⑤ the settlement data of the single point displacement meter in the process of simulating shield excavation is collected.
Because the settlement of the soil body is determined by the excavation gap, the shield tail gap and the filling conditions of the excavation gap, the shield tail gap and the shield tail gap, the invention simulates the tube piece through the fixed built-in steel cylinder, simulates the excavation gap through the outer annular water layer and simulates the shield tail gap through the inner annular water layer, the filling conditions are simulated through grouting, and meanwhile, the single-point displacement meter is used for monitoring the settlement of the soil body to study the law. The simulation test platform can realize the following functions:
under the condition of setting different excavation gaps and shield tail gaps, different-depth soil body settlement data are collected through a single-point displacement meter, and the settlement rule of the soil body caused by shield tunnel excavation is researched.
And secondly, setting the excavation gap and the shield tail gap under a certain condition, acquiring settlement data of soil bodies at different depths through the single-point displacement meter, comparing the settlement difference of the single-point displacement meter of the original state soil and the ultra-deep backfill soil in the soil layer at the same depth, and researching the correction rule of the monitoring settlement value of the single-point displacement meter for drilling at different ultra depths.
Thus, it should be understood by those skilled in the art that while exemplary embodiments of the present invention have been illustrated and described in detail herein, many other variations and modifications can be made, which are consistent with the principles of the invention, from the disclosure herein, without departing from the spirit and scope of the invention. Accordingly, the scope of the invention should be understood and interpreted to cover all such other variations or modifications.
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