CN109183770B - Installation method of pore water pressure meter in soft foundation area - Google Patents
Installation method of pore water pressure meter in soft foundation area Download PDFInfo
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- CN109183770B CN109183770B CN201810987859.4A CN201810987859A CN109183770B CN 109183770 B CN109183770 B CN 109183770B CN 201810987859 A CN201810987859 A CN 201810987859A CN 109183770 B CN109183770 B CN 109183770B
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- pressure meter
- pore
- sleeve
- hydraulic pressure
- water pressure
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- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
- E02D1/00—Investigation of foundation soil in situ
- E02D1/02—Investigation of foundation soil in situ before construction work
- E02D1/027—Investigation of foundation soil in situ before construction work by investigating properties relating to fluids in the soil, e.g. pore-water pressure, permeability
Abstract
The invention discloses a method for installing a pore water pressure meter in a soft foundation area, which comprises the steps of firstly detecting the position and the depth of a soft soil layer, drilling a hole, putting a sleeve into the hole for forming, cleaning the sleeve by using water, draining accumulated water, and pouring cement mortar to the bottom of the sleeve through a high-pressure water pipe; the bottom of the pore hydraulic pressure meter is fixed by a pipe cap, the top end of the pore hydraulic pressure meter is connected with a reducer union, the reducer union is connected with a PVC pipe, a plurality of small holes are drilled on the circumferential surface of the pore hydraulic pressure meter and wrapped by non-woven geotextile, the pore hydraulic pressure meter is placed in the middle of a soft soil layer along a sleeve, and the PVC pipe extends out of the ground; filling broken stones into the sleeve to the depth of the soft soil layer, inserting rubber plugs into the top surfaces of the broken stones, filling cement mortar to the top of the sleeve and covering the PVC pipes exposed out of the ground; and taking out the sleeve and placing a concrete protection device on the top surface to finish the installation of the pore water pressure meter. The method effectively reduces the damage rate of the pore water pressure meter, and improves the accuracy of monitoring data, thereby accurately evaluating the soft foundation treatment effect and the stability of the roadbed.
Description
Technical Field
The invention relates to an installation method of a pore water pressure meter in a soft foundation area.
Background
The pore water gauge is mainly applied to underground water pressure monitoring in the engineering fields of landslides, water conservancy dams, foundation pits, reservoirs, roadbeds, soft foundations, ports and the like. In the construction of the highway, when the highway passes through soft foundation areas such as marshland and the like, most of the roadbed sections are located in deep peat soil areas, and the thickness of the peat soil in partial areas exceeds 10m, so that a large number of water pressure meters are required to be installed for monitoring so as to evaluate the soft foundation treatment effect, the roadbed stability and the like in order to ensure the safety of the roadbed and the side slope.
Generally, a pore water pressure meter is installed by adopting a lower pipe embedding or direct embedding backfilling mode, and a conventional installation method is adopted for a soft foundation area, so that the pore water pressure meter is very easy to damage, effective monitoring data cannot be obtained frequently, and judgment on stability of a roadbed and a side slope is influenced.
Disclosure of Invention
The technical problem to be solved by the invention is to provide the installation method of the pore hydraulic pressure meter in the soft foundation area, the method overcomes the defects of the traditional installation mode of the pore hydraulic pressure meter, effectively reduces the damage rate of the pore hydraulic pressure meter, and improves the accuracy of monitoring data, thereby accurately evaluating the soft foundation treatment effect and the stability of a roadbed.
In order to solve the technical problem, the installation method of the pore water pressure meter in the soft foundation area comprises the following steps:
the method comprises the following steps that firstly, a standard penetration test is adopted to detect the position and the depth of a soft soil layer at the position where a pore water pressure meter is installed, and the pore water pressure meter needs to be placed to the middle position of the soft soil layer;
drilling by adopting a water-jet drilling mode, and putting the sleeve with the PVC cover at the bottom for forming a hole, wherein the drilling depth is greater than the bottom depth of the pore hydraulic pressure gauge by 1 m;
step three, cleaning the sleeve by using water, pumping out accumulated water in the sleeve by using a water pump, inserting a high-pressure water pipe into the bottom of the sleeve, and pouring cement mortar to the bottom of the sleeve through the high-pressure water pipe, wherein the thickness of the cement mortar is 1 m;
fixing the bottom of the pore hydraulic pressure meter by using a pipe cap, connecting the top end of the pore hydraulic pressure meter with a reducer union, connecting the reducer union with a PVC pipe, drilling a plurality of small holes on the circumferential surface of the pore hydraulic pressure meter and wrapping the small holes by using non-woven geotextile, placing the pore hydraulic pressure meter in the middle of a soft soil layer along a sleeve, and extending the PVC pipe out of the ground;
step five, after cement mortar at the bottom of the sleeve is condensed and dried, filling broken stones into the sleeve to the depth of the soft soil layer, inserting rubber plugs penetrating through the PVC pipes into the top surfaces of the broken stones, then filling cement mortar to the top of the sleeve and covering the PVC pipes exposed out of the ground;
and step six, after the cement mortar at the upper section of the sleeve is solidified and dried, taking out the sleeve and placing a concrete protection device on the top surface to complete the installation of the pore hydraulic pressure meter.
Further, the pipe diameter of pore water gauge is 50mm, long 450mm, reducer union is for reducing to 25mm from 50mm, PVC pipe diameter is 25 mm.
Furthermore, the pore diameter of a plurality of pores on the circumferential surface of the pore hydraulic pressure meter is 5mm, the pore distance is 25mm, and the thickness of the non-woven geotextile is 1.5 mm.
Furthermore, the granularity of the macadam is 5-10mm,
further, the diameter of the rubber stopper is slightly greater than 110mm, and the thickness is 10 cm.
Further, the PVC pipe extends to the ground by more than 1 m.
The installation method of the pore water pressure meter in the soft foundation area adopts the technical scheme that the method firstly detects the position and the depth of the soft soil layer, and the pore water pressure meter needs to be placed to the middle position of the soft soil layer; drilling and putting the sleeve into the hole to form a hole, wherein the depth of the drilled hole is more than 1m of the bottom depth of the pore water pressure meter; cleaning the sleeve with water, draining accumulated water, and pouring cement mortar to the bottom of the sleeve through a high-pressure water pipe; the bottom of the pore hydraulic pressure meter is fixed by a pipe cap, the top end of the pore hydraulic pressure meter is connected with a reducer union, the reducer union is connected with a PVC pipe, a plurality of small holes are drilled on the circumferential surface of the pore hydraulic pressure meter and wrapped by non-woven geotextile, the pore hydraulic pressure meter is placed in the middle of a soft soil layer along a sleeve, and the PVC pipe extends out of the ground; filling broken stones into the sleeve to the depth of the soft soil layer, inserting rubber plugs into the top surfaces of the broken stones, filling cement mortar to the top of the sleeve and covering the PVC pipes exposed out of the ground; and taking out the sleeve and placing a concrete protection device on the top surface to finish the installation of the pore water pressure meter. The method overcomes the defects of the traditional pore water pressure meter installation mode, effectively reduces the damage rate of the pore water pressure meter, and improves the accuracy of monitoring data, thereby accurately evaluating the soft foundation treatment effect and the stability of a roadbed.
Drawings
The invention is described in further detail below with reference to the following figures and embodiments:
FIG. 1 is a schematic view of a method for installing a pore water pressure gauge in a soft foundation area according to the present invention;
fig. 2 is an enlarged schematic view of a portion a of fig. 1.
Detailed Description
Embodiment as shown in fig. 1 and 2, the installation method of the pore water pressure meter in the soft foundation area comprises the following steps:
firstly, detecting the position and the depth of a soft soil layer 2 by adopting a standard penetration test at the position where a pore hydraulic pressure meter 1 is installed, wherein the pore hydraulic pressure meter 1 needs to be placed to the middle position of the soft soil layer 2;
drilling by adopting a water-jet drilling mode, and putting the sleeve 3 with the PVC cover 31 at the bottom into the hole to form a hole, wherein the drilling depth is greater than 1m of the bottom depth of the pore water pressure meter 1;
step three, cleaning the sleeve 3 by using water, draining accumulated water in the sleeve 3 by using a water pump, inserting a high-pressure water pipe into the bottom of the sleeve 3, and pouring cement mortar 4 into the bottom of the sleeve 3 through the high-pressure water pipe, wherein the thickness of the cement mortar is 1 m;
fixing the bottom of the pore hydraulic pressure meter 1 by using a pipe cap 11, connecting the top end of the pore hydraulic pressure meter 1 with a reducer union 12, connecting the reducer union 12 with a PVC pipe 13, drilling a plurality of small holes on the circumferential surface of the pore hydraulic pressure meter 1 and wrapping the small holes by using a non-woven geotextile 14, placing the pore hydraulic pressure meter 1 into the middle position of the soft soil layer 2 along the sleeve 3, and extending the PVC pipe 13 out of the ground; the PVC pipe is used for preventing water at a position other than a soft foundation from entering the pore water pressure meter, the water pressure can be measured through the measuring rope, and if the PVC pipe is not arranged, the measured result is the water level elevation instead of the water pressure;
after cement mortar 4 at the bottom of the sleeve 3 is condensed and dried, filling broken stones 5 into the sleeve 3 to reach the depth of the soft soil layer 2, inserting rubber plugs 6 penetrating through PVC pipes 13 into the top surfaces of the broken stones 5, filling cement mortar 4 to the top of the sleeve 3, and covering the PVC pipes 13 exposed out of the ground;
and step six, after the cement mortar 7 on the upper section of the sleeve 3 is coagulated and dried, taking out the sleeve 3 and placing a concrete protection device 8 on the top surface to complete the installation of the pore water pressure meter 1.
Preferably, the pipe diameter of pore water pressure meter 1 is 50mm, and is 450mm long, reducer 12 is for reducing to 25mm from 50mm, PVC pipe 13 pipe diameter is 25 mm.
Preferably, the pore diameter of a plurality of pores on the circumferential surface of the pore water pressure meter 1 is 5mm, the pore distance is 25mm, and the thickness of the non-woven geotextile 14 is 1.5 mm.
Preferably, the crushed stones 5 have a particle size of 5-10mm,
preferably, the diameter of the rubber plug 6 is slightly larger than 110mm, and the thickness is 10 cm.
Preferably, the PVC pipe 13 extends above 1m of the ground.
The method places the pore water pressure meter in the gravel package, and underground water permeates through the gravel and a plurality of small holes on the circumferential surface of the pore water pressure meter, so that the precision of monitoring data is improved; and cement mortar is poured into the bottom surface and the top surface of the broken stone, and a rubber plug is arranged between the top surface and the cement mortar, so that the defect that the pore water pressure meter is easy to damage in a soft foundation area is overcome.
The method effectively solves the problems that the pore water pressure meter is easy to damage, inaccurate in reading and the like in the soft foundation area, and is suitable for installation and monitoring of deep peat soil and other soft foundation areas. The method reduces the damage rate of the pore hydraulic pressure meter in the construction and monitoring processes, improves the effectiveness of the monitoring data of the pore hydraulic pressure meter, and improves the soft foundation treatment effect and the evaluation accuracy of the roadbed stability; the method is convenient to operate, simple and easy to implement and low in installation cost.
Claims (6)
1. A method for installing a pore water pressure meter in a soft foundation area is characterized by comprising the following steps:
the method comprises the following steps that firstly, a standard penetration test is adopted to detect the position and the depth of a soft soil layer at the position where a pore water pressure meter is installed, and the pore water pressure meter needs to be placed to the middle position of the soft soil layer;
drilling by adopting a water-jet drilling mode, and putting the sleeve with the PVC cover at the bottom for forming a hole, wherein the drilling depth is greater than the bottom depth of the pore hydraulic pressure gauge by 1 m;
step three, cleaning the sleeve by using water, pumping out accumulated water in the sleeve by using a water pump, inserting a high-pressure water pipe into the bottom of the sleeve, and pouring cement mortar to the bottom of the sleeve through the high-pressure water pipe, wherein the thickness of the cement mortar is 1 m;
fixing the bottom of the pore hydraulic pressure meter by using a pipe cap, connecting the top end of the pore hydraulic pressure meter with a reducer union, connecting the reducer union with a PVC pipe, drilling a plurality of small holes on the circumferential surface of the pore hydraulic pressure meter and wrapping the small holes by using non-woven geotextile, placing the pore hydraulic pressure meter in the middle of a soft soil layer along a sleeve, and extending the PVC pipe out of the ground;
step five, after cement mortar at the bottom of the sleeve is condensed and dried, filling broken stones into the sleeve to the depth of the soft soil layer, inserting rubber plugs penetrating through the PVC pipes into the top surfaces of the broken stones, then filling cement mortar to the top of the sleeve and covering the PVC pipes exposed out of the ground;
and step six, after the cement mortar at the upper section of the sleeve is solidified and dried, taking out the sleeve and placing a concrete protection device on the top surface to complete the installation of the pore hydraulic pressure meter.
2. The installation method of the pore water pressure meter in the soft foundation area as claimed in claim 1, wherein: the pipe diameter of pore water pressure gauge is 50mm, long 450mm, reducer union is for reducing to 25mm from 50mm, PVC pipe diameter is 25 mm.
3. The installation method of the pore water pressure meter in the soft foundation area according to claim 1 or 2, characterized in that: the pore diameter of a plurality of pores on the circumferential surface of the pore hydraulic pressure meter is 5mm, the pore spacing is 25mm, and the thickness of the non-woven geotextile is 1.5 mm.
4. The installation method of the pore water pressure meter in the soft foundation area as claimed in claim 3, wherein: the granularity of the macadam is 5-10 mm.
5. The installation method of the pore water pressure meter in the soft foundation area as claimed in claim 3, wherein: the diameter of the rubber stopper is greater than 110mm, and the thickness is 10 cm.
6. The installation method of the pore water pressure meter in the soft foundation area as claimed in claim 3, wherein: the PVC pipe extends to the ground for more than 1 m.
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| Application Number | Priority Date | Filing Date | Title |
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| CN201810987859.4A CN109183770B (en) | 2018-08-28 | 2018-08-28 | Installation method of pore water pressure meter in soft foundation area |
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| CN201810987859.4A CN109183770B (en) | 2018-08-28 | 2018-08-28 | Installation method of pore water pressure meter in soft foundation area |
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| CN109183770B true CN109183770B (en) | 2021-08-13 |
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| CN110411646A (en) * | 2019-07-09 | 2019-11-05 | 中铁十四局集团大盾构工程有限公司 | Formation pore hydraulic pressure force test device, production method and its application method after a kind of shield tunnel wall |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104805822A (en) * | 2015-04-03 | 2015-07-29 | 水利部交通运输部国家能源局南京水利科学研究院 | Single-pore multi-point pore water pressure meter embedding fixing device and embedding method thereof |
| CN104963329A (en) * | 2015-07-07 | 2015-10-07 | 天津水运工程勘察设计院 | Soft foundation pore pressure meter embedding method |
| CN105421324A (en) * | 2015-11-09 | 2016-03-23 | 上海达华测绘有限公司 | Burying method for pore water pressure gauges |
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Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104805822A (en) * | 2015-04-03 | 2015-07-29 | 水利部交通运输部国家能源局南京水利科学研究院 | Single-pore multi-point pore water pressure meter embedding fixing device and embedding method thereof |
| CN104963329A (en) * | 2015-07-07 | 2015-10-07 | 天津水运工程勘察设计院 | Soft foundation pore pressure meter embedding method |
| CN105421324A (en) * | 2015-11-09 | 2016-03-23 | 上海达华测绘有限公司 | Burying method for pore water pressure gauges |
Non-Patent Citations (1)
| Title |
|---|
| 定向取心钻进与埋设水压计的经验;谭策纵等;《地质与勘探》;19920731;第28卷(第7期);第57页第3点 * |
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