CN112962521A

CN112962521A - Method for conducting collapse treatment by utilizing self-growing flexible dam and application of method

Info

Publication number: CN112962521A
Application number: CN202110137318.4A
Authority: CN
Inventors: 郑明国; 袁再健; 李定强; 廖义善; 黄斌; 梁晨; 王泉泉; 谢真越
Original assignee: Institute of Eco Environmental and Soil Sciences of Guangdong Academy of Sciens
Current assignee: Institute of Eco Environmental and Soil Sciences of Guangdong Academy of Sciens
Priority date: 2021-02-01
Filing date: 2021-02-01
Publication date: 2021-06-15

Abstract

The invention discloses a method for conducting collapse treatment by utilizing a self-growing flexible dam and application thereof. The method comprises the steps of selecting plants suitable for the hillock collapse environment, planting the plants on a water channel in the hillock collapse environment, and adopting appropriate planting measures to guarantee the survival rate, so that a flexible dam is constructed by utilizing plant living bodies, and the silt of the hillock collapse is intercepted. The method realizes the successful planting of plants in the hillock ditch under the condition of no engineering measure assistance, and is the first pure plant hillock treatment measure. The invention effectively overcomes the bottleneck factor of collapse control that large machinery is difficult to enter, not only has low construction cost, but also has simple and convenient later management because the flexible dam can be automatically heightened later (namely has self-growth characteristic). The invention has good landscape effect and certain economic benefit. The method can realize obvious sand blocking effect in the same year, and can be used for not only treating the unmanaged collapse hills, but also repairing the functions of the silted collapse hills and sand blocking dams.

Description

Method for conducting collapse treatment by utilizing self-growing flexible dam and application of method

Technical Field

The invention belongs to the field of water and soil loss treatment, and particularly relates to a method for conducting collapse treatment by using a self-growing flexible dam and application thereof.

Background

The collapse hillock is an erosion landform type with the greatest erosion intensity and the most serious harm in the south of China, and is like 'ecological ulcer' in the south of China. The erosion of hillock not only damages land resources, but also generates huge amount of silt which buries down-stream farmlands and causes river channel siltation, causing serious ecological and public safety problems. The total number of collapse hills in China is about 23.91 ten thousand, the total area of the distribution area is 48.34 ten thousand km, and the total area is widely distributed in 362 counties (cities and districts) in 7 provinces (autonomous districts) in south of China²The total number of people involved is 1.62 hundred million.

The collapsing hill generally comprises 5 parts of an ascending catchment area, a collapsing wall, a collapsing body, a channel and a alluvial fan.

The research on the collapse of hillock in China has been in history for decades, and the method is mainly based on the treatment modes of 'upper cut, lower cut and middle greening' (also called 'upper cut, lower cut, middle cut and internal and external greening'). The 'upper cut' refers to that a water cut ditch is dug at the top of a hilly hill to intercept runoff which flows into a hilly mouth, the 'lower cut' refers to that a check dam and the like are built at the outlet of the hilly hill, the 'middle greening' refers to that trees and grass are planted in the range of a water collecting area of the hilly hill, and the hilly wall is graded under proper conditions to enable the steep wall to be stepped or be built into a narrow terrace. The method is also beneficial to flattening the hillock by using an engineering machine to achieve the purpose of thoroughly treating the hillock, and the method is only suitable for short hillock and is difficult to apply in regions with large height difference.

At present, no effective method for treating collapsing hills exists, which can be regarded as an old problem which is not solved for decades, and the main reasons are as follows: 1) at present, almost all methods depend on engineering measures seriously, and even some methods called plant measures need to be applied with engineering measures such as 'upper interception', 'lower blockage' and the like so as to ensure the survival of plants. Because the distance of the last hundreds of meters of the place where most of the collapse posts are located is extremely narrow dirt roads or even no roads, large machinery is difficult to enter, and the construction difficulty and cost of engineering measures are obviously increased; 2) the sand-blocking dam (including check dam) is the most common treatment measure for collapsing hills at present, but due to the huge erosion amount of collapsing hills, a huge amount of sand can be silted up to fill the sand-blocking dam in years, so that the sand-blocking function is lost.

Disclosure of Invention

The invention aims to overcome the defects in the prior art and provide a method for conducting post collapse treatment by using a self-growing flexible dam, which has acceptable cost, is simple and easy to maintain, does not need large-scale machinery, and can replace a sand blocking dam.

The invention also aims to provide application of the method for treating collapse hillock.

The purpose of the invention is realized by the following technical scheme:

a method for treating collapse hillock by using a self-growing flexible dam comprises the following steps:

(1) selecting plants suitable for the hillock collapsing environment, planting the plants on a water channel in the hillock, adopting appropriate planting measures to ensure the survival rate, and constructing a flexible dam by utilizing active dry branches of the plants;

(2) and (5) performing later management on the flexible dam.

The flexible dam is also called a plant check dam or a biological dam.

The water channel in the step (1) refers to a ditch bed area of a collapsing ditch, and is generally planted in the whole area without soil preparation.

The water passing channel in the step (1) can also comprise a collapse rush accumulation fan part.

The plants suitable for the collapsing environment in the step (1) are bamboo plants, preferably at least one of sympodial bamboos and mixed bamboos.

The sympodial bamboos are preferably one or two of garcinia hispida and phyllostachys parvus.

The reason for constructing the flexible dam by selecting the bamboo plants is as follows: 1) the ground surface material of the hillock ditch bed mainly comprises quartz gravel which is lack of nutrients, and bamboos are barren-resistant and like loose deep soil layers, so that the hillock ditch bed can better adapt to the characteristic; 2) as a water passing channel, the water conditions in the collapsing ditch are generally the same, and the water immersion duration is short, so that the bamboo growth can be satisfied; 3) bamboo still can survive under silt burying condition, and its mechanism is: the bamboo base generally develops aerial roots, the root points on the stem nodes can also grow adventitious roots, and the aerial roots and the adventitious roots can supply nutrients and water to the bamboo under the condition of burying the bamboo with silt; 4) bamboo can still multiply under the condition of burying silt, and the mechanism comprises the following steps: firstly, the bamboo is asexual propagation, and lateral buds and branches of overground stems of the bamboo can develop into new individuals; secondly, the bud eyes (for sympodial bamboos) or bamboo rhizomes (for scattered bamboos) of the underground stems can also move upwards year by year; 5) the bamboo grows rapidly, the height of the bamboo is increased by more than 10cm in the full period day and night, the bamboo can grow several meters or even dozens of meters in dozens of days, and the sediment deposition rate is far higher; 6) the bamboo plants are widely distributed in the collapsing hill development area, the planting cost is low, and the popularization is easy.

The reason why the bamboo plant is preferably sympodial bamboo or mixed bamboo is that: 1) the hidden buds on the stem of the scattered bamboo are generally less, and the germination capacity is not strong, so the burying resistance is possibly not as good as that of the sympodial bamboo; 2) south China is a main distribution area of the metropolis nationwide, but the south China belongs to the distribution marginal area of the scattered bamboos, and the scattered bamboos are difficult to cultivate, slow in individual growth and small in plant type.

The suitable planting measure in the step (1) is preferably at least one of a close planting measure, a sand bag soil compacting and root protecting measure and a measure for constructing a ridge-ditch alternate terrain. Generally, when the flow rate of water flowing in the water passage is limited, only the close planting measure can be adopted.

The close planting measures are as follows: the row spacing and the plant spacing of the mother bamboos are 1-1.5m and 0.2-0.25 m, and the planting density is far higher than that of the conventional planting.

The sand bag soil-pressing root-protecting measure refers to the following steps: and placing the sandbags on the two sides of the upstream and downstream of each row of bamboos after filling soil.

The sand bag can be a plant growing bag or an ecological bag with good water and air permeability.

The method for constructing the ridge-furrow alternate terrain measures comprises the following steps: soil is taken from planting rows and filled into sandbags, and the sandbags are placed at bamboo stump positions, so that negative terrains are formed among the bamboo rows and are ditches; the bamboo stump part forms a regular terrain which is a ridge (as shown in figure 1).

The measures of close planting, sand bag soil compaction and root protection, ridge and ditch alternate terrain construction and the like are mainly used for resisting the adverse conditions in the collapse hillock ditch and improving the survival rate of the bamboo forest. The most important adversity conditions for bamboo growth in the collapsing channel comprise: 1) strong water flow scouring caused by high-intensity rainstorm in the south; 2) the ground surface material of the channel is mainly loose quartz sand, the high temperature of the ground surface can exceed 70 ℃ in summer, and the bamboo is in a shallow root shape, so the high temperature of the ground surface can cause serious threat. The purpose of close planting is: 1) the bamboo forest is closed as soon as possible, so that the high temperature of the ground surface is effectively prevented; 2) the bamboo likes to gather and grow, and the microclimate formed by the bamboo forest can effectively help the bamboo forest to spend the first year of most difficulty. The alternative topography of furrow can effectively restrain rivers and to the washing away of bamboo root, improves the bamboo forest survival rate. The sandbag soil-pressing root-protecting has the double effects of preventing water flow scouring and surface high temperature damage. Although sand silts can be completely buried and the land form of the furrow can be eliminated by silt deposition after a plurality of heavy rains or one flood period, the mother bamboos survive and are branched and spread leaves, and the stress resistance is obviously improved.

The planting measures in the step (1) also comprise other conventional bamboo forest planting measures.

The other conventional bamboo forest planting measures comprise selection of planting time, selection of plants and the like. Mainly comprises the following steps: 1) the planting time is generally 1-3 months of the dormancy period of the sympodial bamboos and can be planted after rain; 2) the planting rows are vertical to the water flow direction; 3) the height of the mother bamboos is about 1-1.5m, the transportation cost is high when the mother bamboos are too high, and branches and leaves are few when the mother bamboos are too short, so that the photosynthesis after survival is influenced; 4) when planting is carried out after non-rain, enough root fixing water is poured; 5) when planting after 4 months, if the temperature is raised, the bamboo root can be covered by mountain grass, and the bamboo forest can be covered by sunshade net; 6) watering in time when the afforestation is dry for a long time and rainless in the first year.

And (3) performing the later management of the flexible dam in the step (2) basically according to a conventional forest land management scheme.

When the bamboo plants are selected to construct the flexible dam, the management scheme mainly comprises thinning, fertilizing and the like.

Particularly, because the step (1) adopts close planting measures, thinning should be carried out in time at the later stage when the growth space of the bamboo forest is limited.

The intermediate cutting is carried out according to the shape of a Chinese character pin as much as possible so as to ensure that the water flow is fully dissipated in the process of discharging.

The fertilization scheme is generally as follows: the fertilizer application period is 2 years, and the fertilizer is applied once in spring (pregnant bamboo shoot period), summer (early bamboo shoot growing period) and autumn (full bamboo shoot growing period) every year, so that the fertilizer can be applied conveniently.

The conventional management scheme does not involve weeding and ridging, because silt siltation is equivalent to natural ridging, while weeds are difficult to survive in the case of silt siltation.

The application of the collapse treatment method by utilizing the self-growing flexible dam comprises the steps of treating the un-treated collapse by applying the method and repairing the function of the fully silted dam by applying the method, and the purpose of intercepting the silt of the collapse is realized by constructing the flexible dam by using living plants.

Compared with the prior art, the invention has the following characteristics and advantages:

1) the treatment concept is different from the conventional concept: firstly, under the conventional 'upper cut, lower block, middle cut, internal and external greening' treatment mode, all parts of the hilllock are constructed comprehensively, but the invention is only constructed in hilllock ditch; secondly, when plants are planted in the hillock ditch by the conventional method, the planting purpose is soil fixation instead of sand blocking, and the 'flexible dam' concept is not applied to hillock treatment.

2) Although the plants (including bamboos) are planted in the hillock ditches in the precedent, the plants can be guaranteed to survive only by assisting engineering measures such as 'upper cutting, lower blocking' and the like. The bamboo flexible dam is constructed without the assistance of engineering measures such as 'upper cut, lower blocking' and the like, so that the construction cost is low, and the bamboo flexible dam is a post collapse treatment technology adopting a pure plant measure.

3) The dam body of the bamboo flexible dam built by the invention has the self-growth characteristic, namely: in a sediment-silting situation, young bamboos always germinate from the newly silted ground, which results in the bamboo forest being elevated year by year. In fig. 2, the sympodial bamboos are planted in a southern China plant garden in Guangzhou province, and because of annual artificial hilling (the bud eyes of the sympodial bamboos move upwards year by year, and therefore the hilling needs to be done year by year during artificial cultivation), the ground surface is lifted to be close to 1m at present, and the positions of the bamboo stumps of the sympodial bamboos move upwards along with the ground surface, so that the characteristic of self-growth is shown.

4) Because the bamboo flexible dam has the self-growth characteristic, the follow-up maintenance is simple and convenient, but the common sand blocking dam has no self-growth characteristic, needs to be heightened manually after being fully silted up, and has high follow-up maintenance cost.

5) Compared with the common sand blocking dam, the method has good landscape effect and certain economic benefit.

6) The distance of the last hundreds of meters of the collapse hillock is usually an extremely narrow soil road or even no road, and the large-scale machinery is difficult to enter and stay, which is an important bottleneck in the current collapse hillock management. The invention is completely independent of large machinery and can well solve the bottleneck factor.

7) At present, a lot of sand barrages built for managing the collapse hills are full of silt, and lose flood retaining and sand blocking functions. The method can be applied to the treatment of the non-treated collapse hills and also can be applied to the functional repair of the fully-silted dam.

8) Due to the adoption of a close planting strategy, the invention can play a remarkable role in the current year of planting.

Drawings

FIG. 1 is a photograph of planting measures suitable for a hilly trench environment.

FIG. 2 is a photograph showing the "self-growth" phenomenon of the bamboo forest under the condition of artificial earthing.

FIG. 3 is a graph showing the effects of the bamboo forest of example 1 before and after planting.

FIG. 4 is a diagram of the distribution of PVC measuring rods in bamboo groves; (a) each point in (a) and (b) represents a PVC pipe in (c).

FIG. 5 is a photograph showing the variation of sand output from collapse after the flexible dam is implemented; wherein, (a) is the sand basin of the outlet of the collapse hillock of example 1; (b) the left side of the middle part is a sand basin at the outlet of the caving hillock in the embodiment 2, and the upper right part is a sand basin at the outlet of the caving hillock which is not treated; (c) the silt intercepted in a collapsing sand blocking dam near example 2 was obtained.

FIG. 6 is a graph showing the effect of planting bamboo forest in example 2.

Detailed Description

The present invention will be described in further detail with reference to examples and drawings, but the present invention is not limited thereto.

Example 1

This example is to treat the collapse hills which are not treated by the method.

The implementation place is Dongyuan in Hua Town, Wuhua county, Guangdong province, the collapse hillock is not treated, and the confluence area is 8763m²For large collapse, the grass is not grown in the front ditch (left picture of figure 3). The adopted bamboo species are phyllostachys parvus and phyllostachys pubescens, and the planting steps are as follows:

s1: ditching in a ditch bed in the collapsing hillock along the direction vertical to water flow, wherein the width and the depth are both 60cm, placing mother bamboos in the ditches after backfilling loose soil of 20cm, backfilling for 20cm, and treading, and then leveling and treading; wherein the height of the mother bamboos is about 1.5m, the planting row spacing is 1-1.5m, and the planting spacing is about 0.25 m;

s2: after planting, taking soil on the spot, filling the ecological bag with the volume of about 2/3-3/4, and paving the bag on two sides of the bamboo roots;

s3: covering the bamboo roots with mountain grass and covering the bamboo forest with a sunshade net, and removing the bamboo forest after one month because the temperature is high during planting;

s4: after planting, watering root fixing water;

planting effect: the bamboo forest is planted in 26 days of 4 months in 2020, 9 months are basically closed (figure 3), the statistical survival rate at the end of the year is 84%, and the bamboo shoot emergence rate is 25% (table 1).

Silt interception effect 1: in order to measure the sand blocking amount of the bamboo forest (SY1), a total of 62 PVC pipes are inserted into the bamboo forest (figure 4), the burial depth is measured for 1 time every about half month, and the total observation time is 10 times in 10 months; and meanwhile, a sand basin is built at the outlet of the collapse hillock (figure 5(a)), and the deposition amount of the sand basin is also measured through a PVC pipe, so that the silt flowing out of the bamboo forest is obtained (SY 2). The sum of SY1 and SY2 is total erosion amount of collapse hillock, and the ratio of SY1 is bamboo forest interception rate. The calculation result shows that the sand produced by the hillock erosion is 129t in total from 4 months to 10 months and 10 days (close to a complete flood season) in 2020, wherein 86.8t is intercepted by the bamboo forest, and the interception rate is 67% (table 1).

Silt interception effect 2: as shown in fig. 5(a), the sand basin at the outlet of the caving hillock has only silt and no gravel, which is significantly different from the silt intercepted by the conventional sand blocking dam (see fig. 5 (c)). The gravel (grain size >0.05mm) content in the formation is typically around 60%, which also indicates a silt hold-up of at least 60% for this example.

Example 2

The embodiment is used for functionally repairing a full-silted collapse sentry blocking dam.

The implementation place is Dongcun city of China city of Wuhua county, Guangdong province, the slope-collapse mouth is built with a sand-blocking dam, but the sand-blocking dam is full of silted grass, and silted grass on the dam ground before treatment cannot grow (figure 6). The collapsing area is 5776m²It is a large-scale collapse hillock. The bamboo is selected from Phyllostachys Pubescens and Phyllostachys floridus.

Planting: bamboo forests are planted in dam lands formed behind the sand blocking dams, and water flow scouring prevention measures are not taken due to the fact that the dam lands are flat. The same as example 1, except that the planting step does not have S2.

Planting effect: the bamboo forest is planted in 19 days 4 months in 2020, the canopy closure is better in 9 months (figure 6), the statistical survival rate in 11 months is 72%, and the bamboo shoot emergence rate is 17% (table 1). Because of continuous high-temperature drought in dozens of days in summer, the bamboo forest happens to have a borer pest, and the bamboo leaves are almost eaten, so that the planting effect is better if no unexpected condition exists.

Silt interception effect 1: in order to measure the sand blocking quantity SY1 of the bamboo forest, a total of 46 PVC pipes (shown in figure 4) are inserted into the bamboo forest, the burial depth is measured for 1 time every half month, and the total observation is carried out for 10 times in 10 months; meanwhile, a sand basin is built at the outlet of the collapse hills (fig. 5(b)) for measuring the sand SY2 flowing out of the bamboo forest. The sum of SY1 and SY2 is total amount of broken hills, wherein SY1 accounts for the bamboo forest interception rate. The calculation result shows that the sand produced by the hillock erosion is 105t in total from 4 months to 10 months and 10 days (close to a complete flood season) in 2020, wherein the sand is intercepted by the bamboo forest for 102.2t, and the interception rate is 98% (table 1).

Silt interception effect 2: as shown in FIG. 5, the silt is only in the sand basin at the outlet of the caving hills in example 2, but no gravel exists, which shows that the silt interception rate is at least more than 60%.

TABLE 1 basic conditions and planting and sand-blocking effects of the examples

^aExample 1 was planted at 2020/4/26, example 2 was planted at 2020/4/19;

^bexample 1 is the 11-month statistics in 2020, and example 2 is the 1-month statistics in 2021;

^cthe results are obtained from late 4 months to 10 months and 10 days in 2020.

The above embodiments are preferred embodiments of the present invention, but the present invention is not limited to the above embodiments, and any other changes, modifications, substitutions, combinations, and simplifications which do not depart from the spirit and principle of the present invention should be construed as equivalents thereof, and all such changes, modifications, substitutions, combinations, and simplifications are intended to be included in the scope of the present invention.

Claims

1. A method for treating collapse hillock by using a self-growing flexible dam is characterized by comprising the following steps:

(2) and (5) performing later management on the flexible dam.

2. The method for landslide treatment using self-growing flexible dam according to claim 1, wherein:

the water passing channel in the step (1) is a ditch bed area of the collapsing ditch and/or a collapsing fan.

3. The method for landslide treatment using self-growing flexible dam according to claim 1, wherein:

the plants adapting to the hillock environment in the step (1) are bamboo plants.

4. The method for landslide management using self-growing flexible dam according to claim 3 wherein: the bamboo plant is at least one of sympodial bamboos and mixed-growth bamboos.

5. The method for landslide management using self-growing flexible dam according to claim 4 wherein: the sympodial bamboos are one or two of garcinia hispida and phyllostachys parvus.

6. The method for landslide treatment using self-growing flexible dam according to claim 1, wherein:

the proper planting measure in the step (1) is at least one of a close planting measure, a sand bag soil compacting and root protecting measure and a measure for constructing a ridge-ditch alternate terrain.

7. The method for landslide treatment using self-growing flexible dam according to claim 6, wherein:

the close planting measures are as follows: the row spacing and the plant spacing of the mother bamboos are 1-1.5m and 0.2-0.25 m respectively;

the sand bag soil-pressing root-protecting measure refers to the following steps: filling soil into the sandbags, and then placing the sandbags on the two sides of the upstream and downstream of each row of bamboos;

the method for constructing the ridge-furrow alternate terrain measures comprises the following steps: and taking soil between the planting rows, filling the soil into sand bags, and placing the sand bags on bamboo stump parts.

8. The method for landslide treatment using self-growing flexible dam according to claim 6, wherein:

when bamboo plants are selected for constructing the flexible dam, the conventional management in the step (2) mainly comprises thinning and fertilizing.

9. The method for landslide treatment using self-growing flexible dam according to claim 8, wherein:

the thinning-out is carried out according to the shape of a Chinese character pin;

the fertilization scheme is generally as follows: the fertilizer application period is 2 years, and the fertilizer is applied once in spring, summer and autumn every year.

10. The use of the method for landslide treatment using a self-growing flexible dam according to any one of claims 1 to 9, wherein: the method for treating the collapse of hillocks by utilizing the self-growing flexible dam is used for treating the non-treated collapse of hillocks, and/or the method for treating the collapse of hillocks by utilizing the self-growing flexible dam is used for functionally repairing the fully-silted dam.