CN-122013747-A - Degradable drain board core board based on degradation control thickness and preparation method

CN122013747ACN 122013747 ACN122013747 ACN 122013747ACN-122013747-A

Abstract

The invention relates to the technical field of foundation treatment engineering, in particular to a degradable drain board core board based on degradation control thickness and a preparation method thereof, comprising a core board body extending along the length direction of a drain board, wherein the core board body is made of degradable high polymer materials through integral extrusion molding, and the core board body consists of a framework unit and a sacrificial unit; the framework unit is used for maintaining bearing stability and continuity of a water passage for a long time in the whole service period of the drain board, the sacrificeable unit is used for participating in bearing and assisting in guaranteeing smoothness of the drain passage in the construction period and the foundation main consolidation period, and is degraded preferentially in the long-time service period after construction to weaken the drainage capacity, the degradation control thickness of the degradable high polymer material is measured through an accelerated degradation test simulating the engineering service environment, and the partition structure of the framework unit and the sacrificeable unit is introduced into the cross section of the core board, so that the drainage capacity of the drain board is controllable in time and space, and the rapid consolidation and the additional sedimentation control in the operation period are both considered.

Inventors

HUO JUNHAO
ZHANG ZHEN
YE GUANBAO
ZHU YUNQING
FAN HUANG
ZHANG XUE
LUO XINYI
ZHANG YUSEN

Assignees

同济大学

Dates

Publication Date: 20260512
Application Date: 20251229

Claims (10)

1. The degradable drain board core board based on degradation control thickness is characterized by comprising a core board body (1) extending along the length direction of the drain board, wherein the core board body (1) is made of degradable high polymer materials through integral extrusion molding, and the core board body (1) consists of a framework unit (2) and a sacrificial unit (3); The framework unit (2) is used for maintaining bearing stability and continuity of a water passage for a long time in the full service period of the drain board, and the minimum wall thickness of the framework unit in the drain direction is t 1 ; The sacrificial unit (3) is used for participating in bearing and assisting in guaranteeing the smoothness of a drainage channel in the construction period and the foundation main consolidation period, is degraded preferentially in the long-term service period after construction so as to weaken the drainage capacity, has the minimum wall thickness of t 2 in the drainage direction and meets t 1 ＞t 2 ; And determining the degradation control thickness h c of the degradable high polymer material through an accelerated degradation test simulating the engineering service environment, wherein the wall thicknesses of the framework unit (2) and the sacrificial unit (3) are required to meet t 1 ≥k 1 ·h c 、t 2 ≤k 2 ·h c respectively, k 1 is a dimensionless coefficient of 1.3-2.0, and k 2 is a dimensionless coefficient of 0.4-0.8.
2. The degradable drain board core based on degradation control thickness as claimed in claim 1, wherein the ratio t 1 /t 2 of the minimum wall thickness t 1 of the skeleton unit (2) to the minimum wall thickness t 2 of the sacrificial unit (3) is 1.8-2.2, and the ratio can ensure that the skeleton unit (2) still maintains certain compression strength for taking bearing and water-passing stability into consideration when the sacrificial unit (3) degrades to a functional failure.
3. The degradable drain board core based on degradation control thickness as claimed in claim 1 or 2, wherein the cross section of the core board body (1) is provided with a plurality of ribs extending along the length direction, vertical drain channels are formed between adjacent ribs, the rib height of the ribs is 2.8-3.8 mm, the clearance between the adjacent ribs is 2.0-3.0 mm, the skeleton rib (21) accounts for 40% -70% of the total rib number, and the sacrificial rib (31) accounts for 30% -60% of the total rib number.
4. The degradable drain board core based on degradation control thickness as claimed in claim 3, wherein the thick tooth areas (22) of the skeleton rib plate (21) and the thin tooth areas (32) of the sacrificial rib plate (31) are alternately arranged along the cross section, 1 thin tooth area is arranged between every two thick tooth areas (22), and the central line distance between the thick tooth areas (22) and the thin tooth areas (32) is 2.5-4.5 mm, so that the water cross section of the drain channel is uniformly weakened, and local water flow siltation is avoided.
5. The degradable drain board core based on degradation control thickness as claimed in claim 4, wherein the thick tooth area (22) of the framework rib plate (21) and the thin tooth area (32) of the sacrificial rib plate (31) are arranged in a combined manner along the cross section of the thick-thin-thick mode to form repeated arrangement units, the width of each unit is 5.5-7.5 mm, and the degradable drain board core is suitable for soft soil foundations with depth exceeding 10m, and gradient regulation of drain capacities of different depths is realized.
6. The degradable drain board core board based on the degradation control thickness of claim 5, wherein the chain extender in the degradable high polymer material is an epoxy chain extender, the toughening agent is ethylene-vinyl acetate copolymer or polycaprolactone, the melt flow rate (190 ℃ per 2.16 kg) of the degradable high polymer material is 5-15 g/10min, the elongation at break is more than or equal to 30%, and the requirements of an extrusion molding process and construction rigidity are met.
7. The preparation method of the degradable drain board core plate based on the degradation control thickness is characterized by comprising the following steps of: The degradable polymer material is prepared by weighing polylactic acid (PLA), aliphatic-aromatic copolyester (PBAT) and functional auxiliary agent according to mass ratio, putting the raw materials into a double-screw extruder, extruding and granulating to obtain degradable polymer master batch; the degradation control thickness h c of the core plate is determined, the prepared degradable polymer master batch is prepared into a sample with the initial thickness of 1.0-2.0 mm according to the preparation standard of a flat sample, a soil body or solution similar to the foundation environment to be treated is adopted as a medium, the flat sample made of the degradable polymer material is placed in an accelerated degradation environment with the temperature of 45-55 ℃, the thickness of the sample is periodically measured, the compression strength or the water flow is synchronously tested, when the thickness of the sample is thinned to be h c plus or minus 0.02mm, the compression strength or the water flow is attenuated to 70-85% relative to an initial value, the subsequent sample is easy to crack or difficult to be completely measured under the clamping of a clamp, and the corresponding average residual thickness is h c ; After the h c value is determined, determining the minimum wall thickness t 1 of the skeleton unit (2) and the minimum wall thickness t 2 of the sacrificial unit (3) after t 1 ≥k 1 ·h c 、t 2 ≤k 2 ·h c and t 1 /t 2 of 1.8-2.2, preferably 2.0 are met, and meanwhile, meeting the rib plate arrangement of the core plate body (1), so that the skeleton rib plates (21) and the sacrificial rib plates (31) are arranged in a staggered mode; And (3) integrally extruding and molding, namely putting the prepared degradable polymer master batch into a single-screw extruder, setting the barrel temperature to be 170-195 ℃, the die head temperature to be 180-200 ℃, the traction speed to be 1-3 m/min, the degradation control thickness h c , the minimum wall thickness t 1 of the skeleton unit (2) and the minimum wall thickness t 2 of the sacrificial unit (3), extruding by using a die, cooling, shaping and cutting to obtain the degradable drain board core board.
8. The preparation method of the degradable drain board core board based on the degradation control thickness of claim 7, which is characterized in that the mass ratio of polylactic acid to aliphatic-aromatic copolyester is 60-80:40-20, the functional auxiliary agent is 0.1-3.0 parts by mass of chain extender or toughening agent, the raw materials are put into a double-screw extruder, melted and blended at the processing temperature of 160-190 ℃ and the screw rotating speed of 20-40 r/min, and the degradable polymer master batch is obtained through extrusion granulation.
9. The preparation method of claim 8, wherein the temperature of the twin-screw extruder is set to 160-170 ℃ in a segmented manner, 175-185 ℃ in a feeding section and 180-190 ℃ in a compressing section; the temperature of the single screw extruder is set to 170-180 ℃, 180-190 ℃ in a compression section and 185-195 ℃ in a homogenization section in a segmentation mode, the temperature of a die head is adjusted according to the thickness of a core plate, and the temperature of a die head region corresponding to a thick tooth region (22) is 5-10 ℃ higher than that of a thin tooth region (32), so that melt mold filling uniformity is ensured.
10. The method for preparing the degradable drain board core plate based on the degradation control thickness of claim 8, wherein the cooling shaping is performed by water bath cooling, the water temperature is controlled to be 20-30 ℃, the cooling length is 1-2 m, the traction speed is matched with the extrusion speed, the deviation of the cross section size of the core plate is less than or equal to +/-0.05 mm, and the uniformity error of the wall thickness is less than or equal to 5%.

Description

Degradable drain board core board based on degradation control thickness and preparation method Technical Field The invention relates to the technical field of foundation treatment engineering, in particular to a degradable drain board core board based on degradation control thickness and a preparation method thereof. Background The prefabricated vertical drain board (prefabricatedverticaldrain, PVD for short) is widely applied to soft soil foundation treatment of ports and docks, site backfill, high-speed railways, municipal roads and the like due to high construction efficiency and low material cost. In the existing engineering, non-degradable plastics such as polypropylene (PP), polyethylene (PE) and the like are generally adopted as the core plate material of the drain board, and a nonwoven geotextile is wrapped to form a drain channel, so that the soft soil consolidation is accelerated. However, in the engineering with high pile load and long design life, although the long-term maintenance of larger drainage capacity is favorable for shortening the main consolidation time, the continuous development of additional sedimentation after construction can be caused, and the problems of uneven sedimentation, ballast bed slurry and structure cracking and the like of roadbeds or storage yards occur in the operation period. Engineering often hopes that the drainage plates have higher rigidity and water-passing capacity in the construction period and the main consolidation stage, and the drainage capacity can be moderately reduced in the later operation stage so as to slow down subsequent consolidation and additional sedimentation, which is difficult to realize in the existing rigid core plate products, and forms a technical contradiction that high drainage is required in the construction period, high rigidity is required, and moderate drainage capacity is hoped to be reduced in the operation period. In recent years, attempts have been made at home and abroad to use degradable polymer materials such as polylactic acid (PLA), aliphatic-aromatic copolyester (PBAT) and the like for the drain board core board so as to automatically degrade, reduce the drainage capacity or completely exit from working after a period of service. However, the existing degradable drain board mostly uses the equal-thickness rib plate structure of the traditional PP/PE core board, and the drain function is regulated only by the attenuation of the integral strength and the rigidity of the material along with time, on one hand, the attenuation process of the rigidity and the water-passing capacity is difficult to design in advance and quantitatively control, and on the other hand, the degradation rate of the degradable material can be obviously influenced by different environment temperatures, media (soft soil or underground water) and stress levels, so that engineering design is highly dependent on experience. In addition, regarding the structural design of the degradable drain board core board in the prior art, the geometric parameters such as rib plate height, rib distance, winding area and the like are mainly focused, quantitative connection between material degradation behavior, section geometric parameters and drainage function evolution is not established, and a system design method for preferential degradation of a core board local area and drainage capacity control according to time sequence is lacking. Disclosure of Invention In view of the above-mentioned problems that the quantitative relation between the material degradation behavior, the section geometric parameter and the drainage function evolution is not established, and the system design method for the core plate local area preferential degradation and the time sequence drainage control is lacking, the invention is provided. Therefore, the invention aims to provide a degradable drain board core board based on degradation control thickness and a preparation method thereof. In order to solve the technical problems, the invention provides the following technical scheme that the degradable drain board core board based on degradation control thickness comprises: The water draining board comprises a core board body extending along the length direction of the water draining board, wherein the core board body is made of degradable high polymer materials through integral extrusion molding, and consists of a framework unit and a sacrificial unit; The framework unit is used for maintaining bearing stability and continuity of the water passage for a long time in the full service period of the drain board, and the minimum wall thickness of the framework unit in the drain direction is t 1; The sacrificial unit is used for participating in bearing and assisting in ensuring that a drainage channel is unobstructed in a construction period and a foundation main consolidation period, and is degraded preferentially in a long-term service period after construction so as to weaken drainage capac