水泥噴凝植生敷蓋技術在陡坡上之現地應用、調查及其材料最佳化配比之初步試驗研究

Abstract

本研究使用水泥噴凝植生敷蓋技術(Shotcrete Vegetation Mulching Technique,SVMT)於石門水庫嵩台高達80度以上之陡坡進行現地噴植試驗。此外，亦針對SVMT之材料配比進行最佳化試驗研究。於上述試驗中，分別針對不同齡期之試體進行表面強度、土壤pH值以及植生覆蓋情形之相關調查。 首先由現地噴植之各項調查結果顯示，SVMT試體因水泥之固化作用，於施工後3~7天之表面強度即達2.72kg/cm2以上，顯示此一技術可快速提高坡面之土壤強度；而由於試體材料中添加水泥，使土壤於齡期14天前之pH值約為8~9，而於齡期14天後，則因降雨、養護澆水、淋洗以及綠化添加劑之中和，土壤pH值下降至7.4~7.9且趨於穩定；在植生覆蓋度方面，於試體齡期126天時，整體植生覆蓋度已達85%以上，同時於齡期84天起發現原生種植物入侵情形，至齡期242天，試區中共有10種植物入侵，其中以大花咸豐草所占之覆蓋情形最高。綜合上述現地試驗之調查結果顯示，SVMT試體於陡坡上，可在短期內達到一定強度並可提供適合植生生長之棲地環境，且原生物種亦可自然入侵，達到植生綠化及棲地改良之目的。 SVMT之材料最佳化配比試驗選用三種不同土壤，即嵩台現地之土壤、台北市公館淨水場之淨水污泥及石門水庫之淤泥。此三種土壤分別添加水泥、肥料、中和劑及草種。結果顯示配比之表面強度於1.5至5.5 kg/cm2之間，其植生覆蓋度較佳；再者，由土壤pH值及植生覆蓋調查結果顯示，淨水污泥加入硫酸亞鐵之土壤pH值較接近中性且植生覆蓋度較佳。由上述結果可初步得知，淨水污泥及硫酸亞鐵應可分別用作SVMT之土壤及中和劑。

In this study, a newly developed method, namely, Shotcrete Vegetation Mulching Technique (SVMT) was applied on the slopes of Shun-tai at Shih-men Reservoir with steepnesses higher than 80 degrees. Aside from this, a preliminary study on the SVMT material optimum mixture was also carried out. Both the tests in the field and in the laboratory, including surface strength, soil pH value and vegetation coverage, were conducted on the soil surfaces with different ages. Firstly, because of hardening effect of the concrete cement, the surface strength of the soil with the age from 3 to 7 days reached at least 2.72 kg/cm2, indicating that the SVMT method could be used to rapidly increase the strength of the soils on steep slopes. And since the soils were mixed with concrete cement, the pH values of the soils with the age less than 14 days were about 8 to9. When the ages were greater than 14 days, the soil were neutralized because of rainfall, water spraying, leaching and greening additives, the soil pH value were decreased in a stable range from 7.4 to7.9. Regarding vegetation coverage, when the age of the soil was 126 days, the vegetation cover rate had already reached at least 85%. In addition, it was also found that while the age was 84 days, the test site was invaded by native plant. When the age was 242 days, 10 native plants including mostly Spanish needles [ Bidens pilosa L. var. radiate (BI.) Sherff ] were found in the test site. From the results, it might be concluded that the method of SVMT could be applied on steep slopes, providing higher strengths within a shorter time period and habitat environments suitable for plant growing. In addition to these, native plants were allowed to invade into the areas naturally. In regard to the study of the material optimum mixture of SVMT, three soils, namely, soils A, B and C were used. Soil A was collected from Shun-tai, Soil B was from water sludge of the water treatment plant at Gung-guan, Taipei and soil C was the sludge of Shin-men Reservoir. The three soils were mixed with concrete cement, fertilizer, soil neutralizer and grass seeds respectively. The strengths of the mixtures between 1.5 to 5.5 kg/cm2 had better vegetation coverage. Apart from this, from the test results of soil pH value and vegetation coverage, it was found Soil B mixed with ferros sulfate (FeSO4．7H2O) had better soil pH and vegetation coverage. It might be concluded that water sludge and ferros sulfate could be used as the soil and neutralizer of the SVMT respectively.