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为改善生物灌浆诱导碳酸盐在粉土中沉积扩散范围不足和沉积的不均匀性,采用电渗生物灌浆方法(EBM)在粉土中进行灌浆试验。首先研究了不同电压梯度下,脲酶活性的变化规律,在此基础上研究电场下微生物诱导碳酸钙在土中的沉积规律,并与重力灌浆和0.3 MPa低压灌浆方式的沉积效果进行比较。试验结果表明:脲酶活性随电压梯度的增大而降低;电压梯度影响碳酸盐的沉积和分布,当电压梯度在1.0 V/cm附近时,测得的碳酸钙含量沿场强方向变化范围为5.8%~9.6%,碳酸钙的沉积量较多,分布较均匀,而电压梯度为0.5,1.5 V/cm时碳酸钙沉积相对减少,故EBM灌浆的电压梯度宜取1.0 V/cm左右,过低,电渗驱动作用不明显,超过1.5 V/cm,生物活性受到抑制,碳酸钙沉积量反而降低;同土质条件下,重力灌浆的碳酸钙分布范围为0.8%~10.6%,0.3 MPa低压注浆为3.9%~10.2%,故电渗条件有利于生物质在土体孔隙中扩散,使碳酸钙分布更均匀,是一种值得关注的生物灌浆方法。
To improve the bio-grouting-induced carbonate deposition in the silt in the scope of inadequate diffusion and deposition of non-uniformity, using electro-osmotic bio-grouting method (EBM) grouting in silt. Firstly, the changes of urease activity under different voltage gradients were studied. On the basis of this, the deposition rules of calcium carbonate in soil under electric field were studied and compared with those of gravity grouting and 0.3 MPa low pressure grouting. The results showed that the urease activity decreased with the increase of voltage gradient. The voltage gradient affected the deposition and distribution of carbonate. When the voltage gradient was around 1.0 V / cm, the content of calcium carbonate measured along the direction of field strength was 5.8% ~ 9.6%, calcium carbonate deposition more uniform distribution, and the voltage gradient 0.5,1.5 V / cm calcium carbonate deposition is relatively reduced, so EBM grouting voltage gradient should take about 1.0 V / cm, too Low, electroosmotic drive is not obvious, more than 1.5 V / cm, biological activity was inhibited, but the amount of calcium carbonate decreased; with soil conditions, the gravity grouting of calcium carbonate distribution range of 0.8% to 10.6%, 0.3 MPa low pressure injection Pulp is 3.9% ~ 10.2%, so the electroosmosis is conducive to the diffusion of biomass in the soil pores, so that the distribution of calcium carbonate more uniform, is a biofilling method worthy of attention.