CN113920691A - Red layer residual soil landslide quantitative early warning system based on temperature and humidity effect - Google Patents

Red layer residual soil landslide quantitative early warning system based on temperature and humidity effect Download PDF

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CN113920691A
CN113920691A CN202111174925.4A CN202111174925A CN113920691A CN 113920691 A CN113920691 A CN 113920691A CN 202111174925 A CN202111174925 A CN 202111174925A CN 113920691 A CN113920691 A CN 113920691A
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CN113920691B (en
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黄钟焕
鲁光银
李建中
李健民
王玲
吴坤妮
黄秋铭
胡天扬
谢麟
贵仁
车立刚
王荣坛
陈西
曾子芫
涂龙
蒋加杰
张升彪
赖东平
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Huizhou Construction Engineering Quality Inspection Center
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Abstract

The invention provides a red layer residual soil landslide quantitative early warning system based on a temperature-humidity effect. Wherein, red layer residual soil landslide early warning model based on warm and humid effect still includes: the early warning module under the action of moisture absorption, the landslide early warning module of rainfall characteristics and the temperature effect landslide early warning module are respectively arranged, comprehensive evaluation on the landslide of the residual soil in the red layer is carried out on real-time data collected by a soil body temperature and humidity meter, and when a sudden change value appears in a calculation result of any one of the modules or the calculated result exceeds a preset limit value, early warning is informed.

Description

Red layer residual soil landslide quantitative early warning system based on temperature and humidity effect
Technical Field
The invention relates to the technical field of landslide early warning, in particular to a quantitative early warning system for landslide of red layer residual soil based on a temperature-humidity effect.
Background
A large number of geological disasters occur in China every year, and landslides account for a large proportion of the geological disasters. In 2010-2019, the landslide disaster number is more than 50% of the total number of all geological disasters each year. The existing research shows that the occurrence of landslide frequency is influenced by seasons, and the probability of landslide frequency occurrence is the largest in summer with sufficient rainwater. In recent years, the number of accidents of landslide geological disasters in south China is obviously higher than that in other areas, and the occurrence of the phenomenon has a direct relation with soft rock soil and frequent rainfall in the area.
Monitoring and analyzing the stability of the slope becomes one of means for avoiding disasters and reducing loss. In the domestic engineering, the proposal of Japan landslide countermeasure technical association is often consulted, and the displacement rate is adopted to judge whether the side slope is stable, the judging method is to obtain the displacement rate by dividing the measured soil displacement by the observation time and then to combine the displacement rate and the displacement tendency as the basis, but the adaptability to the soil in different areas is uncertain. At present, the slope stability early warning method mainly comprises the following steps: deformation, groundwater level, pore water pressure, deep layer displacement, etc. In geological disaster forecast, only qualitative forecast is involved for atmospheric rainfall, and on the basis of large-scale statistical analysis, a large amount of heat is released before landslide, and the early warning of rapid temperature rise is also only established on the basis of experience, so how to further establish a monitoring and early warning model of the red layer residual soil slope on the basis of the existing test, and establish a landslide monitoring and early warning system by depending on engineering projects, and the construction of the red layer residual soil landslide early warning method based on rainfall characteristics is the most technical problem to be solved at present.
Disclosure of Invention
Aiming at the technical problems, the invention provides a red layer residual soil landslide quantitative early warning system based on a temperature-humidity effect, which comprises the following steps:
s1: detecting the water content and the temperature value inside the rock-soil body by adopting a soil body temperature and humidity sensor laid in the soil body in a drilling embedding mode or a pre-embedding mode, and transmitting the monitoring data to a monitoring center in real time by utilizing a remote wireless transmission mode after digitally processing the acquired signals;
s2: and constructing a red layer residual soil landslide early warning model based on a temperature-humidity effect, calculating the landslide possibility of the interior of the soil body, and triggering an early warning system and a result issuing system to early warn the soil body about to generate landslide when each index of the soil body exceeds a landslide early warning value.
The red layer residual soil landslide early warning model based on the temperature and humidity effect further comprises:
the shear strength of undisturbed soil is measured through a direct shear test, the moisture content of the undisturbed residual soil, the soil body cohesive force c of a soil sample and the internal friction angle phi of the soil body are measured, and a pre-warning module under the moisture absorption effect is established based on the relation between the shear strength and the moisture content of the soil;
or an NLJY-10 type artificial rainfall simulation system, a pipeline system, a spray head, a rain gauge, a water pump and a water tank which are connected in a linked mode are adopted to simulate light rain, medium rain and heavy rain respectively through the spray head 1.5mm, 2.5mm and 3.2mm, the opening degree of the spray head, the rainfall intensity and the rainfall time are set, after rainfall is finished, soil samples with soil body depths of 0cm, -30cm, -60cm and-90 cm are taken out to perform data analysis, and a landslide early warning module with rainfall characteristics is constructed;
or measuring the shear strength of the red layer residual volume cohesive remolded soil by using a ZJ type strain control type direct shear apparatus to obtain the internal friction angle (phi) and the cohesive force (c) of the soil sample under different water content and temperature, calculating the relation among the water content, the temperature and the shear strength, and establishing a temperature effect landslide early warning module;
and when the calculated result of any module has a mutation value or exceeds a preset limit value, warning is informed.
Wherein, early warning module under the moisture absorption still includes:
calculating the shear strength tau with the unit of Pa, and the formula is as follows:
τ＝C(ω)+σtanφ(ω)；
C(ω)＝0.05469ω2-4.26042ω+100.79167；
Figure BDA0003295038860000021
in the formula, omega is the water content of the red layer residual soil, and omega is less than or equal to a preset water content early warning value; the phi value is the internal friction angle of the soil body, the silty clay is the largest when the phi value is the upper limit value, otherwise, the silty clay is the smallest; σ is applied stress in Pa; wherein, the internal friction angle of the soil sample is rapidly reduced along with the increase of the water content, and the later stage is gradually stable.
The relationship between the internal friction angle phi and the water content omega of the soil body is as follows:
φ＝0.005x3-0.43x2+11.2ω-60.18；
wherein, the internal friction angle phi and the water content omega of the soil body are as follows: with the increase of the water content, the inner friction angle of the soil body sample shows a trend of continuously descending; and along with the increase of moisture content omega, soil body cohesion c reduces, and the fitting curve is:
C＝0.07x3-5.55x2+137.5x-1052.8。
further, the landslide early warning module of rainfall characteristics still includes: when the depth of the soil body is 0cm, the water content of the soil is a descending process along with the increase of the rainfall ending time, and the maximum water content is 20.1% when the highest water content occurs at the end of rainfall; .
Further, the landslide early warning module of rainfall characteristics still includes: when the depth of the soil body is-30 cm, the water content of the soil body increases along with the time of the end of rainfall, the water content of the soil body is a process of increasing firstly and then decreasing, the highest water content occurs about 30min after the end of rainfall, and the maximum water content is 19.3%.
Further, the landslide early warning module of rainfall characteristics still includes: when the depth of the soil body is-60 cm, the water content of the soil body is gradually increased and then reduced along with the increase of the rainfall ending time, and the highest water content is between 30min and 60min after the rainfall is ended.
Further, the landslide early warning module of rainfall characteristics still includes: when the depth of the soil body is-90 cm, the water content of the soil body is increased along with the increase of the rainfall ending time, the water content of the soil body is a process of increasing firstly and then reducing, and the highest water content occurs after 60min after the rainfall ends.
Further, the landslide early warning module of rainfall characteristics still includes: the landslide early warning of rainfall characteristics is that rainfall infiltration is caused, rock soil absorbs moisture and softens, the rainfall infiltration amount reaches the value that the intensity is reduced to the limit value, a landslide is generated, and the following calculation formula is adopted:
Figure BDA0003295038860000031
Figure BDA0003295038860000032
in the formula, theta is a dimensionless water content variable; thetarIs the residual water content; thetasIs the saturated water content, s is the saturation; a, m and n are fitting parameters; k is a radical ofsIs the saturation permeability coefficient.
Temperature effect landslide early warning module still includes:
Figure BDA0003295038860000033
in the formula: t1, T2 are temperatures of two parallel faces perpendicular to the heat transfer direction; h is the distance between two planes; a is the area of heat transfer; t is a time interval; q is the heat transferred from one plane to another; λ is the heat transfer coefficient; wherein, the temperature early warning value: and delta t is less than or equal to a preset temperature early warning value.
In summary, the invention provides a red layer residual soil landslide quantitative early warning system based on the temperature-humidity effect, which detects the water content and the temperature in a rock-soil body through a sensor, digitally processes acquired signals, sends the monitored data to a monitoring center in real time in a remote wireless transmission mode, and establishes a data analysis model by combining rock-soil characteristics, a rock-soil thermodynamic theory, a rock-soil strength and water content change rule and a rock-soil infiltration rule to predict and forecast the rock-soil catastrophe condition and analyze the catastrophe. Wherein, red layer residual soil landslide early warning model based on warm and humid effect still includes: the early warning module under the action of moisture absorption, the landslide early warning module of rainfall characteristics and the temperature effect landslide early warning module are respectively arranged, comprehensive evaluation on the landslide of the residual soil in the red layer is carried out on real-time data collected by a soil body temperature and humidity meter, and when a sudden change value appears in a calculation result of any one of the modules or the calculated result exceeds a preset limit value, early warning is informed.
Drawings
FIG. 1 is a schematic diagram of a red layer residual soil landslide quantitative early warning system based on a temperature-humidity effect.
FIG. 2 is a fitted curve of rainfall intensity of 35mm/h and rainfall time of 1.5 h.
FIG. 3 is a fitting curve of rainfall intensity of 35mm/h and rainfall time of 2 h.
FIG. 4 is a curve fitted with rainfall intensity of 54mm/h and rainfall time of 0.5h.
FIG. 5 is a curve fitted with rainfall intensity of 54mm/h and rainfall time of 1 h.
FIG. 6 is a curve fitted with rainfall intensity of 54mm/h and rainfall time of 1.5 h.
FIG. 7 is a fitted curve of rainfall intensity 54mm/h and rainfall time 2 h.
Detailed Description
In order to make the technical solutions of the present invention better understood, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
As shown in fig. 1, the invention provides a red layer residual soil landslide quantitative early warning system based on a warm-wet effect, which comprises the following steps:
s1: detecting the water content and the temperature value inside the rock-soil body by adopting a soil body temperature and humidity sensor laid in the soil body in a drilling embedding mode or a pre-embedding mode, and transmitting the monitoring data to a monitoring center in real time by utilizing a remote wireless transmission mode after digitally processing the acquired signals;
s2: and constructing a red layer residual soil landslide early warning model based on a temperature-humidity effect, calculating the landslide possibility of the interior of the soil body, and triggering an early warning system and a result issuing system to early warn the soil body about to generate landslide when each index of the soil body exceeds a landslide early warning value.
The red layer residual soil landslide early warning model based on the temperature and humidity effect further comprises:
the shear strength of undisturbed soil is measured through a direct shear test, the moisture content of the undisturbed residual soil, the soil body cohesive force c of a soil sample and the internal friction angle phi of the soil body are measured, and a pre-warning module under the moisture absorption effect is established based on the relation between the shear strength and the moisture content of the soil;
or an NLJY-10 type artificial rainfall simulation system, a pipeline system, a spray head, a rain gauge, a water pump and a water tank which are connected in a linked mode are adopted to simulate light rain, medium rain and heavy rain respectively through the spray head 1.5mm, 2.5mm and 3.2mm, the opening degree of the spray head, the rainfall intensity and the rainfall time are set, after rainfall is finished, soil samples with soil body depths of 0cm, -30cm, -60cm and-90 cm are taken out to perform data analysis, and a landslide early warning module with rainfall characteristics is constructed;
or measuring the shear strength of the red layer residual volume cohesive remolded soil by using a ZJ type strain control type direct shear apparatus to obtain the internal friction angle (phi) and the cohesive force (c) of the soil sample under different water content and temperature, calculating the relation among the water content, the temperature and the shear strength, and establishing a temperature effect landslide early warning module;
and when the calculated result of any module has a mutation value or exceeds a preset limit value, warning is informed.
The moisture absorption of rock soil refers to the process that unsaturated rock soil obtains water from the outside, and is called as moisture absorption. Moisture absorption makes rock and soil obtain water quantity, so that the water content of rock and soil or chemical components in rock and soil and temperature change. Further, the rock-soil structure, the mineral composition and the saturation are changed, so that the rock-soil shear strength is influenced. The moisture absorption research of rock soil comprises water source, moisture absorption condition and supply amount. The increasing sources of the water content of the rock and soil are atmospheric precipitation, surface water, condensed water, other aquifers or water-containing systems and the like. The method specifically comprises the following steps:
(1) moisture absorption effect of atmospheric precipitation. The unsaturated rock-soil body contains soil particles, air and water, and in such a three-phase system, the water movement process has more influencing factors and quite complicated process. In the initial stage of rainfall, if the soil body is dry, the water absorption capacity of the soil body is strong. And the gravity of rainwater, the attraction of soil particles and the like promote the water to permeate into the soil layer. The infiltrated water is attracted by the particle surface to form bound water, which is absorbed into fine capillary pores to form suspended capillary water. Therefore, the rainfall in the early stage of rainy season is almost completely absorbed by the unsaturated rock-soil body, the water content is increased, and seepage is rarely or even not formed at all. After the bound water and the suspended capillary water in the unsaturated rock mass reach the limit, the capacity of absorbing precipitation is obviously reduced. The water content of the soil body is full, the rainfall is continued, and the rainwater is transferred through hydrostatic pressure under the action of gravity.
(2) Moisture absorption effect of surface water body. The surface water body comprises rivers, lakes, oceans, reservoirs and the like which are all water supply sources, the underground water level of a water-bearing layer at the lower part of an unsaturated soil body is lifted, the unsaturated soil body generates a moisture absorption effect, the water level in a bank side slope is changed frequently, and the moisture absorption and dehumidification effects of the unsaturated soil body are obvious.
(3) Moisture absorption effect of the condensed water. When the temperature is reduced, the saturation humidity of the rock-soil body is also reduced, so that water vapor exceeding the saturation humidity can be condensed into water. Generally, less water is formed by condensation, but the effect of condensation on groundwater supply cannot be ignored in places with large day-night temperature difference.
(4) Hygroscopic effect of the aqueous layer. The larger the head difference between the water permeable layer and the adjacent aquifer is, the smaller the thickness of the weakly permeable layer is and the better the vertical water permeability is, the larger the flow rate per unit area is. It is of practical significance to find out the degree of association between unsaturated rock-soil mass and aquifers. Ignoring this connection when draining the aquifer, an incorrect design may be made.
(5) Human activities cause the hygroscopic effect, the supply of irrigation water, industrial and domestic wastewater, and the destruction of water supply and drainage pipelines and the exposure of aquifers cause the hygroscopic effect of unsaturated rock masses in the engineering construction process.
The dehumidification of rock and soil corresponds to the drainage of groundwater, and means that the action process of losing water quantity of rock and soil layers is called dehumidification. The moisture removal effect reduces the water content of the rock-soil body, and the research on the moisture removal effect of the soil body comprises a moisture removal mode, influence factors and a moisture removal amount. The rock-soil mass is discharged to the outside in the form of springs (point discharge), stream discharge to rivers (linear discharge), and evaporation (planar discharge). In addition, water in one aquifer may be drained to the other aquifer. In this case, the latter is supplemented by the former. The underground water is developed by a well or is discharged by a drill hole or a channel, and the underground water is artificially discharged.
Early warning module under moisture absorption still includes:
calculating the shear strength tau with the unit of Pa, and the formula is as follows:
τ＝C(ω)+σtanφ(ω)；
C(ω)＝0.05469ω2-4.26042ω+100.79167；
Figure BDA0003295038860000061
in the formula, omega is the water content of the red layer residual soil, and omega is less than or equal to a preset water content early warning value; the phi value is the internal friction angle of the soil body, the silty clay is the largest when the phi value is the upper limit value, otherwise, the silty clay is the smallest; σ is applied stress in Pa; wherein, the internal friction angle of the soil sample is rapidly reduced along with the increase of the water content, and the later stage is gradually stable.
The relationship between the internal friction angle phi and the water content omega of the soil body is as follows:
φ＝0.005x3-0.43x2+11.2ω-60.18；
wherein, the internal friction angle phi and the water content omega of the soil body are as follows: with the increase of the water content, the inner friction angle of the soil body sample shows a trend of continuously descending; and along with the increase of moisture content omega, soil body cohesion c reduces, and the fitting curve is:
C＝0.07x3-5.55x2+137.5x-1052.8。
rainfall infiltration is a main way for moisture absorption of rock soil, and the rainfall infiltration increases the moisture content of unsaturated soil and reduces the strength, so that the rock soil is damaged, the rainfall infiltration rule is researched, and the method has important significance for researching the catastrophe theory of the moisture content of unsaturated soil. Rainfall infiltration test research an artificial rainfall infiltration test is carried out on undisturbed soil and remolded soil of residual soil, and the rainfall: refers to the depth of rain that falls onto flat ground (assuming no leakage, evaporation, run-off, etc.) within a certain time. Usually measured with a rain gauge in mm.
Rain: refers to drop-shaped liquid precipitation. Raindrops are different in size, clearly visible when falling, small in rainfall intensity change and long in duration.
Light rain: the rainfall is less than 2.5mm within 1 hour, or the rainfall is less than 10mm within 24 hours.
Rain: the rainfall is equal to 2.6-8.0mm within 1 hour, or the rainfall is equal to 10.0-24.9mm within 24 hours.
Heavy rain: the rainfall is equal to 8.1-15.9mm within 1 hour, or the rainfall is equal to 25.0-49.9mm within 24 hours.
Rainstorm: the rainfall is equal to or more than 16mm in 1 hour, or the rainfall is equal to or more than 50mm and less than 100mm in 24 hours.
Heavy rainstorm: it means rain having a rainfall equal to or greater than 1000mm and less than 200mm within 24 hours.
Extra heavy rainstorm: refers to rain with rainfall greater than 200mm within 24 hours.
Rain shower: the method is characterized in that the method refers to paroxysmal rainfall, raindrops are large, the beginning and the end of the paroxysmal rain are all very sudden, the most urgent time of the rainfall is short, the intensity change is large, and the sky changes suddenly and suddenly.
The invention further tests that soil samples with the soil depth of 0cm, -30cm, -60cm and-90 cm are dug by a Luoyang shovel after 30min, 60min and 90min after rainfall is finished.
After a group of tests are finished, the obtained soil sample is taken into a test room for moisture content test, and test results are counted, wherein the data are shown in table 1:
Figure BDA0003295038860000071
table 1 shows: the rainfall intensity is 35mm/h, and the rainfall time is 0.5h.
Figure BDA0003295038860000072
Table 2 shows: the rainfall intensity is 35mm/h, and the rainfall time is 1 h.
Figure BDA0003295038860000081
Table 3 shows: the rainfall intensity is 35mm/h, and the rainfall time is 1.5h of soil body water content.
Figure BDA0003295038860000082
Table 4 shows: the rainfall intensity is 35mm/h, and the rainfall time is 2 h.
Figure BDA0003295038860000091
Table 5 shows: the rainfall intensity is 54mm/h, and the rainfall time is 0.5h of the water content of the soil body.
Figure BDA0003295038860000092
Table 6 shows: the rainfall intensity is 54mm/h, and the rainfall time is 1h, so that the water content of the soil body is increased.
Figure BDA0003295038860000101
Table 7 shows: the rainfall intensity is 54mm/h, and the rainfall time is 1.5h of soil body water content.
Figure BDA0003295038860000102
Table 8 shows: the rainfall intensity is 54mm/h, and the rainfall time is 2 h.
Figure BDA0003295038860000111
Table 9 shows: the rainfall intensity is 131mm/h, and the rainfall time is 0.5h of soil body water content.
Figure BDA0003295038860000112
Table 10 is: the rainfall intensity is 131mm/h, and the rainfall time is 1h, so that the water content of the soil body is increased.
Figure BDA0003295038860000121
Table 11 shows: the rainfall intensity is 131mm/h, and the rainfall time is 1.5h of soil body water content.
Figure BDA0003295038860000122
Table 12 shows: the rainfall intensity is 131mm/h, and the rainfall time is 2 h.
As shown in fig. 2-3, based on the above test data, analyzing the conditions of rainfall intensity of 35mm/h and rainfall time of 0.5h, observing the curve change conditions of the water content of the soil bodies at different depths, and finding that when the depth of the surface soil, i.e. the soil body, is 0cm, the water content of the soil is a descending process along with the increase of the rainfall ending time, and the maximum water content is 19.9% when the highest water content occurs at the end of rainfall; when the depth of the soil body is-30 cm, the water content of the soil is increased along with the time of the end of rainfall, the water content of the soil body is a process of increasing firstly and then decreasing, the highest water content occurs about 30min after the end of rainfall, the maximum water content is 19%, when the depth of the soil body is-60 cm, the water content of the soil is increased along with the time of the end of rainfall, the water content of the soil body is a process of gradually increasing firstly and then decreasing, the highest water content occurs between 30min and 60min after the end of rainfall, when the depth of the soil body is-60 cm, the water content of the soil is increased along with the time of the end of rainfall, the water content of the soil body is a process of increasing firstly and then decreasing, and the highest water content occurs after 60min after the end of rainfall.
And analyzing the rainfall intensity of 35mm/h and the rainfall time of 1h, and observing the curve change condition of the water content of the soil body at different depths, wherein the change trend of the soil body at the depth of 0cm, -30cm, -60cm and-90 cm is basically the same as that of the soil body at the rainfall time of 0.5h.
When the rainfall intensity is 35mm/h and the rainfall time is 1.5h, observing the curve change condition of the water content of the soil bodies with different depths, wherein when the depth of the soil body is Ocm, the water content of the soil is a descending process along with the increase of the rainfall ending time, and the maximum water content is 19.9% when the rainfall is ended; when the depth of the soil body is-30 cm, the water content of the soil is increased along with the time of the end of rainfall, the water content of the soil body is a process of increasing firstly and then decreasing, the highest water content occurs about 30min after the end of rainfall, when the depth of the soil body is-60 cm, the water content of the soil is increased along with the time of the end of rainfall, the water content of the soil body is a process of gradually increasing firstly and then decreasing, and the highest water content occurs between 30min and 60min after the end of rainfall; when the depth of the soil body is-60 cm, the water content of the soil body is increased along with the time of the end of rainfall, the water content of the soil body is a process of increasing firstly and then reducing, and the highest water content occurs after 60min after the end of the rainfall. Comparing the rainfall time of 1.5 hours with the rainfall time of 0.5 hours, we find that the water content of each depth of the soil body is greatly increased and is very close to the value of the highest water content in the period of just finishing rainfall, namely when the rainfall stopping time is 0.
When the rainfall intensity is 35mm/h and the rainfall time is 1.5h, the change process and the change amplitude of the water content of the soil body at each depth are equivalent to the conditions of the rainfall intensity of 35mm/h and the rainfall time of 2 h.
Further, a fitted curve of rainfall intensity 35mm/h was constructed as follows:
Figure BDA0003295038860000131
the rainfall intensity of 54mm/h was analyzed in the same manner as shown in FIGS. 4-5, and the fitted curve is shown in the following table, and the change law thereof is not much different from that in the case of 35 mm/h.
Figure BDA0003295038860000141
Observing curve change conditions of soil moisture content at different depths as shown in FIGS. 4-7, wherein when the soil depth is 0cm, the moisture content of the soil is a descending process along with the increase of the rainfall ending time, the maximum moisture content is 20.1% when the maximum moisture content occurs at the end of rainfall, and a fitting formula of a curve of the soil moisture content along with the change of time is shown in the table; when the depth of the soil body is-30 cm, the water content of the soil body increases along with the time of the end of rainfall, the water content of the soil body is a process of increasing firstly and then decreasing, the highest water content occurs about 30min after the end of rainfall, the maximum water content is 19.3%, and a fitting formula of a change curve of the water content of the soil body along with the time is shown in the table: when the depth of the soil body is-60 cm, the water content of the soil body is increased along with the time of the end of rainfall, the water content of the soil body is a process of gradually increasing and then decreasing, the highest water content occurs between 30min and 60min after the end of rainfall, and the fitting formula of the change curve of the water content of the soil body along with the time is shown in the table; when the depth of the soil body is-60 cm, the water content of the soil body is increased along with the time of the end of rainfall, the water content of the soil body is increased and then reduced, and the highest water content occurs after 60min after the end of rainfall. The fitting equation of the water content of the soil body along with the time under the conditions of different depths is shown as the following table:
Figure BDA0003295038860000151
based on the analysis and experiment principle, the landslide early warning module of rainfall characteristics is constructed, and specifically comprises the following steps: when the depth of the soil body is 0cm, the water content of the soil is reduced along with the increase of the rainfall ending time, and the maximum water content is 20.1% when the highest water content occurs at the rainfall ending time.
Further, the landslide early warning module of rainfall characteristics still includes: when the depth of the soil body is-30 cm, the water content of the soil body increases along with the time of the end of rainfall, the water content of the soil body is a process of increasing firstly and then decreasing, the highest water content occurs about 30min after the end of rainfall, and the maximum water content is 19.3%.
Further, the landslide early warning module of rainfall characteristics still includes: when the depth of the soil body is-60 cm, the water content of the soil body is gradually increased and then reduced along with the increase of the rainfall ending time, and the highest water content is between 30min and 60min after the rainfall is ended.
Further, the landslide early warning module of rainfall characteristics still includes: when the depth of the soil body is-90 cm, the water content of the soil body is increased along with the increase of the rainfall ending time, the water content of the soil body is a process of increasing firstly and then reducing, and the highest water content occurs after 60min after the rainfall ends.
Further, the landslide early warning module of rainfall characteristics still includes: the landslide early warning of rainfall characteristics is that rainfall infiltration is caused, rock soil absorbs moisture and softens, the rainfall infiltration amount reaches the value that the intensity is reduced to the limit value, a landslide is generated, and the following calculation formula is adopted:
Figure BDA0003295038860000161
Figure BDA0003295038860000162
in the formula, theta is a dimensionless water content variable; thetarIs the residual water content; thetasIs the saturated water content, s is the saturation; a, m and n are fitting parameters; k is a radical ofsIs the saturation permeability coefficient.
Further, the dimensionless water content variable Θ is:
Figure BDA0003295038860000163
where ψ is suction force.
Further, the soil-water characteristic curve of the red clay in the test area is determined by a pressure plate instrument as follows: when the saturated water content θ s is 54.6% and the residual water content θ r is 6.4%, the V-G model is fitted with the values of a, n, and m as follows:
fitting parameters Value taking
a 0.006
n 3.175
m 0.994
Temperature effect landslide early warning module still includes:
Figure BDA0003295038860000164
in the formula: t1, T2 are temperatures of two parallel faces perpendicular to the heat transfer direction; h is the distance between two planes; a is the area of heat transfer; t is a time interval; q is the heat transferred from one plane to another; λ is the heat transfer coefficient; wherein, the temperature early warning value: and delta t is less than or equal to a preset temperature early warning value.
The above-mentioned embodiments only express several embodiments of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the present invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention. Therefore, the protection scope of the present patent shall be subject to the appended claims.

Claims (6)

1. The utility model provides a red layer residual soil landslide quantitative early warning system based on warm and humid effect which characterized in that includes following step:
s1: detecting the water content and the temperature value in the rock-soil body by adopting a soil body temperature and humidity sensor laid in the soil body in a drilling embedding mode or a pre-embedding mode, and transmitting the monitoring data to a monitoring center in real time by utilizing a remote wireless transmission mode after digitally processing the acquired signals;
s2: the landslide early warning method comprises the steps of constructing a red layer residual soil landslide early warning model based on the temperature-humidity effect, calculating the landslide possibility of the interior of a soil body, and triggering an early warning system and a result issuing system to early warn the soil body about to have landslide when any index of the soil body exceeds a landslide early warning value.
2. The red layer residual soil landslide quantitative warning system based on temperature and humidity effect of claim 1, wherein the red layer residual soil landslide warning model based on temperature and humidity effect further comprises:
the shear strength of undisturbed soil is measured through a direct shear test, the moisture content of the undisturbed residual soil, the soil body cohesive force c of a soil sample and the internal friction angle phi of the soil body are measured, and an early warning module under the action of moisture absorption is established based on the relation between the shear strength and the moisture content of the soil;
or an NLJY-10 type artificial rainfall simulation system, a pipeline system, a spray head, a rain gauge, a water pump and a water tank which are connected in a linked mode are adopted to simulate light rain, medium rain and heavy rain respectively through the spray head 1.5mm, 2.5mm and 3.2mm, the opening degree of the spray head, the rainfall intensity and the rainfall time are set, after rainfall is finished, soil samples with soil body depths of 0cm, -30cm, -60cm and-90 cm are taken out to perform data analysis, and a landslide early warning module with rainfall characteristics is constructed;
or measuring the shear strength of the red layer residual volume cohesive remolded soil by using a ZJ type strain control type direct shear apparatus to obtain the internal friction angle (phi) and the cohesive force (c) of the soil sample under different water contents and temperatures, calculating the relationship among the water contents, the temperatures and the shear strength, and establishing a temperature effect landslide early warning module;
and when the mutation value appears in the calculation result of any module or exceeds a preset early warning value, informing the early warning.
3. The red layer residual soil landslide quantitative early warning system based on warm and humid effect of claim 2, wherein the early warning module under moisture absorption further comprises:
calculating the shear strength tau with the unit of Pa, and the formula is as follows:
τ＝C(ω)+σtanφ(ω)；
C(ω)＝0.05469ω2-4.26042ω+100.79167；
Figure FDA0003295038850000021
in the formula, omega is the water content of the red layer residual soil, and omega is less than or equal to a preset water content early warning value;
Figure FDA0003295038850000022
the value is the internal friction angle of the soil body, the
Figure FDA0003295038850000029
When the value is the upper limit value, the silty clay is the largest, otherwise, the silty clay is the smallest; σ is applied stress in Pa; wherein, the internal friction angle of the soil sample is rapidly reduced along with the increase of the water content, and the later stage is gradually stable.
4. The quantitative early warning system for red layer residual soil landslide based on warm and humid effect according to claim 3, further comprising an internal friction angle of the soil body
Figure FDA0003295038850000024
The relationship with the water content omega is as follows:
Figure FDA0003295038850000025
wherein the internal friction angle of the soil body
Figure FDA0003295038850000026
The water content omega and the you drink curve are as follows: with the increase of the water content, the internal friction angle of the soil body sample shows a trend of continuously descending; and along with the increase of moisture content omega, soil body cohesion c reduces, and the fitting curve is:
C＝0.07x3-5.55x2+137.5x-1052.8。
5. the red layer residual soil landslide quantitative pre-warning system based on warm and humid effect according to claim 2, wherein the landslide pre-warning module for rainfall features further comprises: the landslide early warning of rainfall characteristics is that rainfall infiltration is caused, rock soil absorbs moisture and softens, the rainfall infiltration amount reaches the value that the intensity is reduced to the limit value, a landslide is generated, and the following calculation formula is adopted:
Figure FDA0003295038850000027
Figure FDA0003295038850000028
in the formula, theta is a dimensionless water content variable; thetarIs the residual water content; thetasIs the saturated water content, s is the saturation; a, m and n are fitting parameters; k is a radical ofsIs the saturation permeability coefficient.
6. The red layer residual soil landslide quantitative pre-warning system based on temperature and humidity effect of claim 3, wherein the temperature effect landslide pre-warning module further comprises:
Figure FDA0003295038850000031
in the formula: t is1、T2Is the temperature of two parallel planes perpendicular to the heat transfer direction; h is the distance between two planes; a is the area of heat transfer; t is a time interval; q is the heat transferred from one plane to another; λ is the heat transfer coefficient; wherein, the temperature early warning value: and delta t is less than or equal to a preset temperature early warning value.
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